Easiest way I can think of is with a paint program (Photoshop etc).

Just clone over the holes during postwork.

A better way would be to follow the steps here http://www.morphography.uk.vu/v3qd.html and use your mesh instead of the quick dress. The section called "Cutting the Cloth" shows you how to fill holes using the free Anim8tor software.

Hope that's usefull to you.