LF Mobo, cpu, ram upgrade under 350

[turtlenumber13]

so I build my computer a few years back and have slowly upgraded alot of stuff. but my mother board and CPU are getting a bit out dated as I still run with a single core. my other problem is I only have 1 gig of ram.
I am a gamer. and I compile alot of data. I make music and videos on my PC.

my current specs are as follows.

P4 3.0 GHz CPU with hyperthreading.
Geforce 8800 GTS SSC EVGA PCI-E 16x (its a pci-e v1 not 2)
1gig corsair ram
1 250 gig sata 1.5ghz hard drive, and 1 500g sata data drive.
1 soundblaster 24bit live! sound card.
1 nic card. (10-100-1000)
~edit. 750w Powersupply

so I need at least 2 PCI slots that are useable while the video card is set up. and hopefully a few USB ports so I can hook up all my sound devices.
if I forgot any info that is needed, post and I'll repley soon as I can.

 

[aliasaid]

Newegg.com - AMD Phenom II X4 955 Black Edition Deneb 3.2GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Processor - Processors - Desktops

Newegg.com - OCZ Obsidian 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model OCZ3OB1600LV4GK - Desktop Memory

Newegg.com - ASUS M4A77TD Pro AM3 AMD 770 ATX AMD Motherboard - AMD Motherboards

total: $345

 

[turtlenumber13]

So its looking to me like amd is the only way to go for a budget now adays?

the hardest thing for me is finding mobo CPU and ram that are compatible.