I am trying to make a Sonic Cake for my son's Birthday Party on Sunday. I found my picture that I want to use. I am not an artist. Can I pipe my design on wax paper and then pull it off and then put it on the cake.

I don't know what size or style of cake you're making but it sounds like what you want is a Frozen Buttercream Transfer.
Here are the instructions. Hope that helps.

http://cakecentral.com/articles/73/how-to-create-a-frozen-buttercream-transfer

can I do this method with all crisco? I have already made the frosting? I don't want to have to go and get more supplies. I am on a major budget.

Definately. As long as it is considered 'buttercream' it can be used for this technique.