I too go to a shcool that uses evaluations rather than grades. However, they advise everyone from the get-go that if you are planning on attending post-grad, you should ask your professor for a grade too. SO that's what I did.... My evluations now have a statement at the end that says "Though this university does not use a grading system, if a grade were assigned it would be an A".
You should check with your school ASAP. I know for our school, you can go back to professors and have them do it even if the course was a couple years ago. I had to do that with a couple who had failed to put the grades on.
The evluations are good though...it's nice to have more than just "A" listed, b/c the professor can read "This student was required to write a 20 page report and it was articulate and awesome" .LOL.