Looking at the photos I would have to agree with some of the other posters that the frame is very rusted. I would also agree that the frame isn't worth welding. And by the looks of the first pic, howbeit it is very fuzzy, that it appears the other side of the brake bridge is also bad. It does appear that someone tried to spread the stays and failed. Welding this bridge back will only buy you time for something else to break like the other side of the brake bridge, and you may pay more for the weld job then what you paid for the bike, and then have to turn around later and do more welding. I would stop the money leak while you can. Strip the parts off the bike, and either sell them on E-Bay to try to recoup some of the money, or keep the parts for another frame.