Easy mate. Take the following to the Madinat Khalifa traffic office:

1. Letter from employer
2. Copy of Qatar id, passport front and back and visa page.
3. Copy of UAE license as well as original.

Get an applicaiton typed outside the traffic department which usually costs QAR10. Then go for an eye test and after that, take the applicaiton and eye test result to the counter and get a new Qatar driving license. I think the fee is around QAR 250 or something.