To be honest, I have seen great crops from both floro's and CFL's. I have seen the best come from a mixture of both though. The CFL's have an advantage over the floro tubes because they can be moved around to feed the desired light to particular areas.

I would stick with the floro tubes you have and add a few CFL's. They are pretty cheap and they really do work.

Floro's
Veg=6500k-daylight cooler
Flower=3000k-warmer

CFL's
Veg=6500k-daylight
Flower=2700k-soft white