How long to win money?

I'm still pretty new to online poker. I find that the money I deposit lasts longer but I still eventually go broke.

I read poker theory as much as I can and try to learn from my mistakes at the table.

I'm currently playing 1/2 shorthanded hold'm. I play about 15 hrs a week. What would be the average time for a player to start beating the game enough to move up?