I need some serious help.

I have been reading these posts on walking puppies. My Marty is 12 weeks old now and our walking is getting worse. When I get up in the morning I want to look forward to walking her, however, it is only discouraging. I walk out the door first, and she follows. But then she will either sit and not budge, or sniff around me and try to go in different directions. I have treats to lure her up to me which once she comes I praise her and give her the treat, but then she won't move ahead again unless she see's me grab for another treat. Eventually, she becomes disinterested in the treat and tries to pull back to the house. I'm getting so discouraged because I want us to bond on our walks but its not happening. Any suggestions would be great. Thank you.