There are several conversion charts on the net that you can use to convert Dimensions floss to DMC. Google around a bit and I'm sure you'll find one you like. I, too, prefer DMC floss so understand your pain; I also find that often Dimensions kits don't have quite enough floss to finish the design.

If you go to Cyberstitchers.com you will find a floss conversion chart for Dimensions floss to DMC floss. I use this website every time I need to do a conversion because I like stitching with DMC floss almost all of the time.