I'd try wrapping the jointwith a thin metal, like a soda can cut flat, then put the clamp back on, before using a new clamp or welding in the v bands. The v bands will seal for sure.

 

take it to a local muffler shop and have a flange welded to the pipes and bolt it to gether that way with a gasket in the middle. something like this http://www.rallyrace.net/images/2003...st_flanges.jpg

that is what I would consinder if I did not want to get it welded together.