I've been looking to upgrade my pc but I am not sure wha would be best. I want it to be able to play RTS games better, and any video game in general better. I plan on keeping what ever i can to save money. the case i have is good to keep and i have a 550w anandtech power supply. the harddrives i have i also plan on keeping. so iaminly looking at cpu, video card, ram, and maybe mother board.

ATI Radeon HD 4800 SeriesVideo Card

4 gigs of ram

Amd athlon II x4 620 2.6GHz CPU

are my current specs. I am open to a price range of 250-400 but I would like to keep it as cheap as possible

http://www.newegg.com/Product/Product.aspx?Item=N82E16814102999

The HD 7850 is a pretty solid card I use on my 2nd machine which has a similar CPU to yours. You could probably get away with keeping the Athlon II but if you wanted to upgrade you could probably slot in this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103727

Which would cost you $85 after the rebate card and it would put your overall bill at less than $300.

Alternatively you could go with something from an Intel flavour if you wanted to pay a little more and get a new motherboard etc.

http://techreport.com/review/24059/tr-christmas-2012-system-guide/2

i3-3220 ~$130
HD 7770 ~$115
Any Compatible motherboard ~$100

Is your motherboard upgradeable to AM3+? You could keep it and get a new AMD CPU for less than i3+Motherboard.

Alternately if you're just looking for higher resolutions or detail spend only on a $200 graphics card like the 7859 or 650 Ti and skip the new CPU.

Also Starcraft II/LoL/Dota are NOT demanding games and I don't see why a 4850 isn't good enough for Ultra.

In your case get this card
http://www.newegg.com/Product/Product.aspx?SID=mVN_Zk8iEeK_TubHJGciMAEXO5_k72N3_sBL_0_0&AID=10440897&PID=1225267&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-cables-_-na-_-na&Item=N82E16814130827

comes free with Assassins Creed 3 as well. Should be good enough for what you want to do.

DO you have a microcenter near you? That have some excellent deals for processors

example: i3 3225 processor $119.99 + $40 off any mobo.

I would say just upgrade the graphics chip and wait until you have enough money and do the whole rest of the system next year.

No point. A better GPU would be throttled by that CPU. 2.6Ghz?? As a lot of RTS' are dependant on a good CPU, he should look into getting a whole new mobo setup. IMO save up for a good i5 as that'll last you for a long time. 

I have been playing a lot of starcraft 2 lately and in matches with more than two people(or ai) i get real bad slow downs. Not sure if its the cpu or video card.

Its definitely the CPU unfortunately. Like someone previously said RTS games tend to be cpu intensive.

Before i did my upgrade recently i was getting shitty FPS (under 30!!) in DOTA 2. I had a decent card 560ti, which should have gien me more than 100 FPS easily!

After just upgrading my CPU i then got those high FPS.

Aside from games being CPU intensive, you also need to remember that most gpu's are dependant on a good cpu. If you cpu is performing badly then this will have a major impact on a good gpu! I would say the major bottleneck in your system at the moment is your cpu and not your gpu

This is what I said.