Mylar can be bought at hobby stores I think and also wal mart.

Where are planning to buy 4 foot 6500K light tubes?

If you can, buy instead the small CFL's. a four foot tube will wste far too much light for two plants. YOu want it direct and concentrated. THe way you currently have it leaning against the wall shining down will not work.

FLoros must be within inches of the plant top.

I mean an inch

So lets start with mylaring the walls and geting some good cfl bulbs.

lose the tubes friend.