Welcome aboard! My DH and I just started in October, it can be VERY overwhelming and you can go into BIG pin overload, not to mention debt!
There are a couple of must use websites:
www.dizpins.com and
www.pinpics.com. Pinpics has a numbering system for each pin. There's no rhyme or reason to it, as new pins come out, numbers are assigned to them. These numbers help alot when you see e-mails in this board and in Dizpins. Also in Pinpics, you can set yourself up to show what you have to trade and what you wish to get. This takes a while to set up (it took me a couple hours), but I've already gotten a couple of good trades out it, so it was worth the time.
Dizpins is a great site too. This site let's you know what pins are coming out and also has discussion boards similiar to this site. On Dizpins though, there's a for sale board, where you can pick up some good deals on pins.
As for purchasing more pins, I call Dis Purchasing (you can get the number off of Dispins) to buy the current rack pins WDW has. If you let the customer rep know up front you're looking for rack pins to buy (rack pins are pins you can buy off any Dis rack - LE's are Limited Edition pins - only so many sold per edition), he or she can help you out. I tell them what specific type of pin, i.e. Monsters Inc. or Snow White and they'll tell you what they have in stock. What I like about them, is you pay the same price you would if you were in WDW, just a little extra for the shipping.
I hope that helps a little! Be sure to check out the pin meet sites on the boards. We went to our first one last Sunday and it was a blast! We met alot of nice people and got some great trades.
Good luck and if you have any other questions, feel free to e-mail me.