Wood grow cab lighting

Greetings fellow RIUers!

I currently have a *wooden* 3x2x1 foot grow cabinet that I use for vegging. I am currently use two 2' t5 lights. I am getting a lot of lower leaves falling off.... which tends to imply that I have insufficient lighting.

I am contemplating installing additional lighting.... but I have some concerns so I thought I would pick other people's brains. Please be advised that I am in Canada and don't have a lot of money so i'm trying to do this on the cheap.

Any ideas on how to do this? Four additional t5 lights would cost around $120 and I am not sure I have that kind of cash right now.

http://www.lightingdirect.com/index.cfm?f359=true&page=search:browse&bathroom-lighting-fixtures=c1742&categoryid=1742&s=price_low

Hopefully that link works, if not try this one: http://www.lightingdirect.com/maxim-990015pb-four-light-bathroom-fixture-from-the-maxim-collection/p860557

These are easy to install and accept most all CFLs which can be found for really cheap most everywhere.