Panel adhesives have become widely used by body shops in recent years. While it's not recommended for structural repairs, it's slowly becoming the preferred method of installing replacement panels, where heat from welding can distort the surrounding sheetmetal.
In your situation, you can just clean up the area, hammer out a patch, glue it in place, tap it down a bit, then apply filler to smooth it out.
Here's some links to check out:
http://www.tech-cor.net/AutoResBulle...6-3/1996-3.htm
http://www.lord.com/Home/ProductsSer...0/Default.aspx
I should also add... you won't need the entire kit for your windshield repair, but it sure looks handy if you plan on hanging any side panels later. There are other manufacturers out there, but most require special applicator guns ranging from $50 - $400 while Eastwood's setup is geared toward the DIY hobbyist.