Help! Green thumb aside i cannot grow Deiffenbachia's for the life of me!

heres the story.

A girlfriend of mine received a plant from her mothers funeral two years ago. She emailed me a couple days ago to see if i'd be able to bring a plant of hers back to life. I picked it up this evening...

The plant is exceptionally leggy and spindly. You can tell it has been over watered and under watered frequently. The leaves its pushing out are very small and lack all variegation.

My problem.

I have NEVER been able to grow them! nor grow them well. And since this plant means so much to her i couldn't look at the pathetic thing and tell her i wouldn't try.

Description

8 inch pot. Good soil with decent drainage. Plant has 10 stalks that go from about a nickle in diameter to the width of a pencil. Stems are up to 18 inches in height with branches differing in length. Each branch has about 3 to 4 leaves just at the tips. Im thinking its Camille just by the small amount of variegation that shows up on a couple of the leaves.... but that could be wrong

I will be doing research regarding the plant itself but i find that actual hands on growing and peoples opinions work better for this situation.

I know it needs better light due to the leggy-ness of the plant. I know you can cut them back... but i dont know how far i should do that... 4 inches from the soil? and how much light can i give this dude?

http://en.allexperts.com/q/House-Plants-721/floppy-Dieffenbachia.htm

is kind of what it looks like (just copy the link) minus the size of the leaves. Id take a picture but im a failure when it comes to embedding. Any advice?