Upgrading to an i3 or i5? My Options available to me?

[ATOTHEJ4]

I bought a desktop about 2 years ago. Its CPU was a Pentium G630 (which for the price is a good performer in my opinion.) A few months back I added a Geforce GTX 750ti and my gaming performance went through the roof. I then bought Far Cry 4 and it couldn't even run (many people saying it was simply because of Ubisoft not supporting dual core CPU's in game.) So my question is - is Dual-core CPU's dead for modern gaming? I am trying to figure this out and get opinions. Should I upgrade just my CPU? I am stuck and can't decide. Obviously I am not an expert in building, but I have done enough to do a complete build. Thanks for any suggestions/opinions/help?

EDIT: I have 8GB RAM of 1066Mhz which I expanded just in the past few months from 4GB. It is non-expandable from 8GB.

Here is some info on my desktop when I bought it:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

* According to Newegg it has the Intel H61 Express Chipset, LGA 1155 (if that helps.)

Just to be clear: I replaced the small form factor case, and replaced it with a larger case over a year ago. Like stated previously I am running the 750ti as well.

EDIT: I was thinking for my budget in mind for a new CPU ($125 or less) my best option would be the i3-3240 for under that price. I would be willing to wait and save for an i5, though at the same time I think I just want something to work and not break the budget. Random question though? Will my current 8GB RAM work with the i3-3240 since it says it supports DDR3-1333/1600? Would I have to get new RAM as well? and given the information above, does my mobo support DDR3-1333/1600? Thanks!

 

[jenojaxx]

outdated socket ! , you should wait and replace the motherboard+cpu , or if not then try buying something like a i5 3570k (second hand) .
but if you wait to replace mobo+cpu , you could turn over the AMD side , cause an fx-6300 or fx-8320/8350 + 30-40$ cooler + a ~ 100-140$ motherboard would be a better value

 

[SuperMassiveScum]

I know this is over your budget but for socket 1155 i'd go for an i5 3570k and if you're not looking to overclock get the non K variant, it's worth saving up for rather than settling for an older i3.

Socket 1155 is a little old now and there is sense on replacing your mobo as the above poster said however if the computer still does it's job and you just need a little more processing power then a nice CPU upgrade will so just fine, in fact a jump this big will probably make quite a big difference.

I have absolutely no bias in recommending the i5 3570k either...

 

[Mr_Venbeer]

A Pentium G3258 or i3-4130 are decent CPU's to pair up with the GTX 750 Ti for now. You should wait to buy a new motherboard and CPU, maybe go with a Broadswell CPU or a faster older gen chip, which will come down it price.