Not worth it. Youd still have to cough up a $200 extra to get a 3770K and comparable motherboard not to mention having to reinstall Windows all over again and if you only have an OEM copy then youre gonna need another $100 for that as well.
I dont think its worth it cause Ivy is only 5% faster than Sandy and really the only place youre going to notice 5% difference is in benchmarks. In real world use, theyd run pretty much the same.
T'aint worth it.