How is it that you can afford over $7000 dollars worth of software but can't go from an i5 to an i7?
School id say!
Go a sandy bridge i7 2600k, a little cheaper and you'll get the 4 cores and HT. Also make sure to go 16GB, i'm also using 2 460 (768Mb) in SLI which is also pretty cheap.
I strongly advise to go a I7...
I use 3DsMax2013, Maya 2013, CS5.0 and all these components are vital if you don't want to tear your hair out.