Which to buy!?!?

I want to purchase this iMac that I have found, but I am unsure if it is faster than the system that I have now.

Current system:
mid 2012 15" macbook pro retina
8 gb ram
500 gb HD
2.6 intel i7 quad core

Possible buy:
2009 27" imac
16 gb ram
1 tb HD
3.06 intel core 2 duo

Would the iMac be faster since it has more ram and a faster processor (even though it is 2 cores)