Nigam98 :
RobCrezz :
You could download speccy and it will tell you what you have:
http://www.piriform.com/speccy
DH55TC i found it which should i go for?
Assuming you have a good CPU cooler, then you can look at this guide to overclocking your I3. You should get 4Ghz which will help avoid any bottlenecks, and you could get the gtx 760.
http://www.tomshardware.co.uk/forum/263043-29-1156-core-core-overclocking-guide