I'd say get the i5, it will perform much better overall, once you get a gpu of course. You could even go with an h81 board to save some more money, since you won't be upgrading much then PCI 3.0 isn't really a factor. Try for 8GB of ram if you can however.
I would go for the AMD fx 6300 great processor and they are quite cheap too and would be all that you will need for running those games at least on medium settings the gpu you want is also good along with the amd processor. you might want to consider a 500w branded PSU to power the PC as amd uses more watts than intel.
This psu is high quality and will be enough to power your system http://www.amazon.co.uk/OCZ-OCZ-ZS550W-UK-Series-Bronze...
If i where you AMD is the way to go if your on a budget you wont regret it.