PrincessJasmine1972,
First & foremost, CONGRATULATIONS! I think you could say that I'm a Disney veteran by now (since 1971!), but in October I'm taking my wife on her first trip to Disney ever, so I know how you're feeling (I've been enjoying the excitement through my wife's eyes now for a couple of months since we finally said we're booking it & making it happen).
Now, on to your questions:
1. How far in advance should I book our stay?
I'd recommend booking as early as possible. You will NOT have to pay too much of it in advance, you'll be able to cancel if things change, and most importantly, you'll KNOW FOR CERTAIN when you're going & that you're going where YOU want to.
2. Is it better/cheaper to go through a
travel agent or Disney?
I've booked it directly and with a travel agent. This trip out, I decided to use a travel agent (Small World Vacations, another
travel agency that specializes only in Disney travel) to help make sure that I got the best rates that I could, as well as to ensure that someone ELSE could sweat the details. They do make sure to try for a better rate for you if one comes out, as do many of the specialized agents. They're also better to answer your questions you might have as a WDW newbie. You might also choose to request a quote from a couple of different travel agencies and decide not just who has the best price (they'll often all have the same price), but also who "feels" the most "right" to deal with.
3. Which resorts do you have to stay at to have the benefit of the EMH's? ( I was told only the Deluxes)
All the DISNEY properties have EMH benefits. That also does include the Swan & the Dolphin. Everything from the Value resorts up through the Deluxe resorts can take advantage of the extra magic hours. (note that at the end of this, I'll let you know a bit about a couple of things that MIGHT make a difference to you in deciding where to stay at)
4. Is it better to use your car(we will be driving down)to get around the World or it is better to use the busses/ferry/monorail?
It will partly depend on where you're staying and when you're going. How bad the traffic will be depends on what's going on at the time (Xmas holidays for example, you'll have more trouble getting anywhere no matter what method you use). However, two important things to keep in mind. The buses pick up in a certain order... if you're on the tail end of the pick up, you may be more likely to have to stand. Also, when you're going to the Magic Kingdom, you will ALMOST certainly want to use Disney transportation, regardless of what you decide for the other parks; MK parking is the worst of the lot.
5. How early should I get to the parks to get hubby an
ECV?
I'm using an ECV myself this trip out (have in the past had to consider renting one for a day or so, but this trip, if I plan to see anything, I'm going to need it most of the time). If you're thinking of getting him an ECV for just "a day", you MIGHT consider the WDW
ECVs at the park (but I wouldn't necessary recommend it!). If, on the other hand, you're getting him one that you'll likely use for more than just 1 day, I'd suggest you don't even think about using the WDW ones; rent from one of the off-site locations that will deliver it to the bell desk & have it waiting for you when you arrive. Depending on what resort you're at, it might be that you'll find he needs it just to get around the resort (some of them are pretty spread out, & don't know just what it is that he may be needing it to help with). For our upcoming trip, I called all of the ones listed in the disABILITY forum and finally decided on Walker. Their price was relatively competitive (only 1 place was lower, but, I did not feel comfortable with what the rep said on the phone... made me concerned about potentially "bad" business practices), and the Walker rep was by far the nicest & easiest to deal with on the phone. They got an A+ for pre-WDW customer service already.
6. What are the best restaurants for the money and is the Dining Plan any good?
Best restaurants completely depends on what you like to eat, how much you eat normally, etc. For this trip, we're doing the Dining Plan & will be paying for it (arrive a little too late to catch the Free Dining Plan offer), but, for us, we're pretty certain that it'll be a good deal.
Now, I did promise to include one or two things that you might find important/useful to know when you're considering resorts. First of all, the Swan & Dolphin are on Disney property, even though they're not Disney resorts. You do get the benefits of EMH, but do not have Disney-wide charging privileges to your room. On the other hand, you may qualify (or may not, you know your circumstances, I don't) for one of the special rate discounts that they have (government employee, teacher, etc). Consider checking that out, as the Swan & Dolphin (or as one of the Podcasts calls them, the Swolphin) are more "deluxe" hotels but do not charge the same as the Disney-owned deluxe hotels, if you qualify for one of the discounts.
The only other thing that I can recommend is that you consider subscribing to one or more of the available podcasts about Disney. You can often find out things you never knew about WDW on them, hear about things that are changing before they necessarily become "fully" public knowledge, etc. Plus, depending on which podcast you decide to go with, they can just plain be FUN.
Enjoy your trip, & feel free to respond here OR leave me a message if you've got any questions. Also, do check out the disABILITY forum on here for a lot more information that might be useful for you &/or your husband.
I know you all will help me as much as possible... 
Making those memories soon.
!
.
