Making my PC Faster? -help-

Hello, i've been searching in 5boxxing with 1 computer or so i was thinking about a thing.

I have windows 7 32bit.
When i open the CPU USAGE, i have 2046mb total
Core 1 and core 2
I have geforce 9500 1000mb (or 1052, can't remember around that)

I can run WoW on high graphics and 1680x1050 resolution.
I can 5 multibox on the computer, some lagg but tinzy resolution and really bad graphics
I can play MW2, CSS and other games on -HIGH- and almost everything used, so all details are fine.

So now, i was wondering if i can/how can i upgrade my computer?

Since i have 2046mb i was thinking i could buy 2000mb more (How much would this cost? and would it help?)
And should i upgrade to a 64bit? i heard that 32bits CAN MAX HAVE 3000mb.

So, Do i need something special to actually buy more cpu usage space or so, or is it just to go to a store and ask for it? and they sell me, i put it into my computer and it's done? (How much would that cost too? for 2000mb upgrade or around that)

And should i get a 64bit windows 7? instead of 34, help please.

You should upgrade to Win 7 64 bit as stated in other post.
You need more RAM, usually 1 gb per toon. We cannot tell you how much and what type of RAM without knowing what motherboard you have.
The cores can be dealt with in WoW or in your Boxing software, you want to use all the cores you can.
The GPU is not that strong but fix the first two then try it out.