I like what Cheetah said IMO. If you feel that you cannot beat .5-1 level, you will struggle even more at 1-2. However, the way I see it is, if you can beat the .25-.5 game so easily, and you are making enough money to do whatever you want to do with then maybe consider staying at the level you're at atm.
It's taken you less than a month to treble the $600, so there's no reason why you cannot keep making around $1200 a month
. Put that into perespective and that is still $24,000 a year at the level you are at right now. So perhaps you do not even need to move up at all.
On the other hand, stick to the game you play at .25-.5 and move up again to .5-1 it could just be a stage you are going through, perhaps its abad run that will even itself out, or maybe you are playing like scared money. If you play the same way, and addapt to the new level, i'm sure you will end up winning even more money.
gl with your venture, gl at the tables all