What do you think?

I have a late 2009 Imac 27" 3.06 Intel Core Duo 1TB HDD 8GB ram

I'm thinking about upgrading my mac, I built a power house gaming pc with i7 4770k and GTx770 GPU

But I still love mac, and the only reason I built it was to play games, I don't have the big toy budget that i used to but I really want to upgrade.

I have them side buy side at my glass desk and I use the mac mainly for doing all my work and picture editing for my web site with pixalator but nothing much else, regarding mass graphics, I am a computer guy and love electronics but most of all I love my mac.

So the question is..

Should I just buy a mac mini i7 and put it under the imac and use the imac for a monitor?

would that make sense? I cant afford a new imac as much as I would love one, also will the Mac Mini be better then my imac or is there no point in upgrading?

I also don't know how much life i will get out of this computer for much longer regarding the monitor.

Thanks in advance.