Core 2 Duo

I have a core 2 Duo clocked at 2.7ghz
I'm planning on an upgrade by getting 8gigs of ram and the Gtx 750ti
I'm not gonna play at 1080p I just want decent playable Fps in med to high settings at 1366x768.
Is a CPU upgrade absolutely necessary? 
I really am running short on cash and even if I want,the best I can get is a core-i3
So, can I get decent gaming without upgrading the CPU?

Depending which generation you have. If you have a wolfdale you can clock it to 3.2 or even 4ghz easily (e7300 and e8400 are great chips). Do not get an i3, the performance boost doesn't warrant an upgrade to a slightly better dual core. Save some money and get a proper quad core like an i5 or i7 4770.

A 750ti is a good card for your system but you might want to get the cheaper r9 270, it's a bit better, especially for your resolution. If you manage to overclock your CPU you won't really need to upgrade for most games out now.

I recommend you read this, and keep in mind haswell has 5-10% better performance than ivy bridge:

http://www.tomshardware.com/reviews/ivy-bridge-wolfdale-yorkfield-comparison,3487.html

I have an E8400 at home you can have if you want, literally sitting on my shelf doing a whole lot of nothingness. Pay postage ($5 or something) and it's yours, then you can overclock the knackers out of it.

I really appreciate you trying to help but I already have E7300 and it would probably be useless for me too :) 

Again, thanks.

 

Some more opinions would be nice though.

if you have a motherboard chipset that allows for decent overclocking (p35, P43, P45, X38, X48) then you should have no real problem overclocking it substantially. I got a E8200 up to 3.8 GHz with a core voltage set at 1.355. Just make sure that you adjust your RAM for stability.