The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
A search and browsing of the plant forum here will answer a lot. If you find a post by Rex Grigg, look at his sig, which has a link to his FAQ which is good info, though more geared at a higher light tank.
To answer your question outright, 2 watts per gallon, and some patience.