Urgent help sun damage - Dracaena Marginata

Well, I wouldn't repot it. It's stressed enough.
You could try a little feed but other than that, I think it's just keeping your fingers crossed.

After i posted this question, I read that in case it sheds all its leaves one can crop the stems to any desired length and the new leaves will apprear shortly, also the top parts can be simply stuck into the same pot, and they are likely to give roots and new leaves too. I am going to repot it and chop it up as well (it will actually help it looking more full and proportionate)
This tree was outside the house when we bought it in 2005 and it looked pretty stressed then and it did survive and was happy enought, although the foliage never looked very full, unlike my other dracaena. It was also pale green with burgundy edges- the other one is much deeper green. I read it has something to do with the lighting.
Anyway, fingers crossed it will revive again. I am going to keep the story live on my homepage.

These are quite common outdoor garden and potted plants over here in northern Oz, so I was surprised to hear that it didn't do well outdoors. Maybe the soil dried out quickly - they do like a moist growing medium, but they don't like being over-watered either. They do drop their bottom leaves as the stem grows taller - that's normal. If you do crop and re-pot, try regular misting of the lower stems and leaves with some tepid water. This plant will strike from stem sections lopped off the mature plant. The colours do develop more when the plant gets some shade.

Well, good luck with it, hun. I hope it revives. It'd be lovely to see it when it does. :o)