Bugdet rig upgrade help!

Hey guys!
I need help choosing future parts... I want to buy a new cpu by next month and upgrade graphics later depends how much spent on cpu and how much i can gain...
My specs:
Intel Pentium 4 Ht 524 Socket 775 @ 4.0ghz
Abit Fatal1ty fp-in9 650i sli
EVGA 9600gso 384 mb version
Corsair Xms2 2gb 800mhz kit
Seagate 120gb sata drive
Dynex 400 watts
random 40gb pata drive
Windows Xp sp2

Ok first off i need a bugdet cpu priced $0-$100 dual cores at least and at least 2mb l2 cache. Im realy thinking about a e5200... if i buy that itll take me about 6 months to upgrade graphics card... if i buy the e2220 which only has 1mb chache, i can upgrade graphics in 4 moths, and if i buy e7300 ill upgrade graphics in a year...

Now for graphics... i have the 9600gso which i got brand new for $50. awesum card but idk if the 384mbs can keep up with new games... so i was thinking since motherboard is sli, would this system be good...
e5200
9600gso sli
or would it be better to w8 till newer cards come out.... maybe push 4870s lower or a new bugdet card comes out??
also can i sli the 9600gso 384mb with the 9600gso 768mb???

well then ill need a new psu too!