Upgrades

http://www.newegg.com/Product/ComboBundleDetails.aspx?I...

You can pick out a gpu in your price range..

Market price for a decent build
You can get a stronger CPU (i3 3220) but will have to get lower graphics (7770)

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Pentium G860 3.0GHz Dual-Core Processor ($65.99 @ NCIX US)
Motherboard: ASRock B75M-DGS Micro ATX LGA1155 Motherboard ($58.98 @ SuperBiiz)
Memory: Patriot Viper 3 8GB (2 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Video Card: MSI GeForce GTX 650 Ti 1GB Video Card ($109.99 @ Newegg)
Power Supply: Cooler Master GX 450W 80 PLUS Bronze Certified ATX12V Power Supply ($29.99 @ Newegg)
Total: $304.94
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-01-26 17:36 EST-0500)

With the combo you do get an a quad core but its llano so its stars cores are really like a athlon IIx4 @2.6-2.8 and the PSU is a bit on the weaker side. It does come with a case though. Need to price the ram and gpu

why do i need a new case when i already have a bigger one?

In that case go my build XD

get it? "case"  

There is actually a 620W ANtec Neo Eco on sale for $29.99 so get that instead of the GX

link

http://pcpartpicker.com/part/antec-power-supply-neoeco6...

btw this is my new gaming rig i have 8gb of ram in my old system and a gtx550ti as well so could i over clock the cpu in that combo? my athlon x3 has a 4.00 overclock

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Pentium G860 3.0GHz Dual-Core Processor ($65.99 @ NCIX US)
Motherboard: ASRock B75M-DGS Micro ATX LGA1155 Motherboard ($58.98 @ SuperBiiz)
Video Card: XFX Radeon HD 7850 1GB Video Card ($159.99 @ Newegg)
Power Supply: Antec Neo Eco 620W 80 PLUS Certified ATX12V / EPS12V Power Supply ($29.99 @ Newegg)
Total: $314.95
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-01-26 21:21 EST-0500)

You can overclock with the baseclcok but it all depends on the luck how far you can push that. Some people have had great success, others less so. 3.3 would be about all I would expect
Went with the 7850 to differentiate more from the 550ti you're using already