That's rough. I have an i7-3770K and an i5-3570k and for many things the i7 is just a whole lot better, so that would be a really good upgrade. However, I also have an Asus p8z77-v LE and it's wimpy. Does the job with the i5, but much prefer the ability of my MSI Mpower Z77 (pretty much the same as the Gene).
The i5-2500k will work directly on the Gene, but the i7-3770K will need the latest bios on your p8p67 as it's a move from Sandy-Bridge to Ivy-Bridge. You'd get the most immediate use from the 3770k on your existing board as long as the OC was mediocre, you'll not be able to keep a good high OC stable though, the board isn't made for it. You'll not be able to really open up that i7 until you get the Gene.