Like some of the other posters have said, the plants should be much more developed by 8 weeks. If I were you, I would probably order some seeds for my next grow right now, and go ahead and get that 600w light ordered. In the meantime, add the extra cfls you have to your current grow, and ride it out for another 2 weeks. I don't think I'd waste my time past 10 weeks (max) if they haven't gotten much chunkier than they are now. The longer you wait, the longer it is until you can start growing some big ass buds. If you can buy seeds or clones locally, I would scrap this grow immediately, and start a new one tomorrow. You don't need the 600w for the first few weeks of the next grow anyway, especially if you have to germ seeds, etc...You're not going to yield much on this grow, at all, and the quality is going to be questionable at best. That said, I've found that the people on this site are generally helpful, there's an unlimited quantity of grow info to read and learn from, and you'll get better over time.
But yeah, try to get that next grow started as quickly as possible, and in the meantime add whatever lights you can.