How much do you love the Kona frame? Think long and hard about the upgrade. It might make sense to tide you over until you can afford a new bike but for whatever reason you may be happier with the new bike now.

I have a Cannondale, my first small road bike, I loved her so I spent the money upgrading shifters, derailleur, cassete and put a carbon fork on her. A year later I bought a carbon frame because I was tired of being beaten to death by the harsh ride. I still have that bike, she's my trainer bike and the one my out of town friends ride.

Then 2 years ago I made changes to my cf bike. I have over 10k miles on it since the changes so it was money well spent, however, I'm not sure it was money well spent for the Cannondale.

Good luck with whatever you decide.