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.