Mousesavers is definitely a good place to look.
Since your trip is coming up soon, you could also look into using Priceline for your room, if you're willing to stay off-site. If you go this route, there are a couple of websites that show you what people are paying for rooms, where the Priceline hotels are located, etc. One is biddingfortravel and the other is betterbidding (all these websites I've listed are .com)
Also, take a look at Bookit and TravelZoo. Sometimes they have some good deals.
I believe there's also a Swan and Dolphin promotion that brings their rooms down to around $119 a night, but I'm not sure what the timeframe is.
One thing to remember is that if you do stay off-site, your transportation needs also increase. Some offsite hotels have shuttles, but your park visits are then on their schedule, not yours. If you stay at a Disney resort, you get Magical Express for free, which gives you transporation to and from the airport and once you're on-property, you have free access to the Disney transportation system. Car rentals can be expensive now, so the free Magical Express is definitely something to factor in.
If you do opt to rent a car, book something now, but continue to check the rates as your trip approaches. There are sometimes huge changes in rental price as you get inside a week or two (but sometimes the rate goes up, which is why you should book now).
