Looking for a GPU upgrade, also possible bottleneck question

[Kasai]

Ok, first I'll start with the bottleneck question.

Still running a computer that I got ~4 years ago and I've been in the process of wanting an upgrade but I'm also a poor college student. Given that, my current relevant specs are as follows:

Core2Duo 6600 Overclocked to 2.7GHz
8800GTS

Now my main question. On the account that I need a CPU+Mobo+Ram combo in order to upgrade my CPU, it's somewhat out of the question at this point. If I were to upgrade my GPU, would the CPU bottleneck the system enough to not make it worth it?

Second question:
I haven't even really looked at GPUs in ~4 years when I last bought my computer. Could someone recommend a good cost-efficient card for <150$?

Tl;dr version:
-Recommend a good, cost-efficient GPU for <150$
-Given the current CPU, would upgrading even be worth it or would the CPU bottleneck the system too much? Would it be better to save my 150$ and put it towards the CPU+Mobo+Ram purchase?

Thanks in advance.

[chewgo]

I'd say save, if you upgrade the whole system really nicely then you'll have something that will last a lot longer. Your current setup isn't doing too badly.

[Kasai]

Well, the reason I ask is because I'm getting decently poor performance in a few games and I'm looking to boost with with the new GPU. Mainly I just wanted to know if buying a new GPU would give me a decent boost given the CPU.

Edit: After looking around I'm trying to decide between two cards:
[url]http://www.newegg.com/Product/Product.aspx?Item=N82E16814150447[/url] - Radeon HD 5770
[url]http://www.newegg.com/Product/Product.aspx?Item=N82E16814150477&cm_re=Radeon_5850-_-14-150-477-_-Product[/url] - Radeon HD 5850

What would be the decision between these two cards. Is the extra 50 bucks worth the 5850?

[breakyourface]

I have the same processor as you, mines not even overclocked so it's stock at 2.4ghz. I have a bfg 9800gt+ and I'm running bulletstorm maxed out with no AA at 1680x1050 you shouldn't have much of a bottleneck unless you have no ram.

[Kasai]

Yeah, ram isn't a problem.

Anyway, I ended up getting the 5850 after reading around. It should be quite a nice change.