You'll have to clean the paint right around the join to make it work.
It is possible to either solder or braze the join back together - soldering will work, but I'm cranky and prefer to braze (brazing is stronger.)
The difference between the two is heat and filler - soldering is typically done at around 700-800*F, with an alloy of tin/silver, tin/lead, tin/silver/bismuth, or some other mix (silver-bearing solders are usually tin/silver or tin/silver/bismuth - or sometimes tin/bismuth.) Solder will flow readily into a join, but it is difficult to patch a large hole with - since it flows so easily. Also, soldering does not chemically "join" the metal parts - it merely "fixes" them together with a soft filler metal. Soldering will work on similar and dissimilar combinations.
Brazing is still not a fusion process (like welding,) but it involves higher temperatures and different alloys. Brazing works closer to the fusion/melting temperature of the base metal, and will usually use a filler metal that is closer in composition to the base metal (but usually with a somewhat lowered melting point.) While brass is a combination of tin and copper, a brazing rod for brass will usually have a higher tin concentration, or have bismuth added, to lower the melting temperature - which means the base metal parts don't have to be melted to be joined. Brazing will also work on combinations of similar or dissimilar metals - but it is usually thought of as a process for dissimilar metals. Careful selection of brazing rod is necessary for proper brazed joins.
Welding is a fusion process, where enough heat is applied to melt the base metal. By addition of a filler metal, the "gap" between the parts (there usually is one,) is eliminated, and the metal at the join flows together to make, effectively, a single part. I've covered all these processes in detail elsewhere, and I'm thinking it might not be a bad idea to do a FAQ on them one of these days (right after I finish the cooling system FAQ and a couple other things...)
Make sure to get some paint (prefereably radiator paint, but for small areas any regular flat black will work) to cover the area after you repair it. Allow a minimum of two hours after you braze/solder before you put the unit back in service - no sense in straining a fresh braze/solder join unnecessarily (and since heat and pressure are both invovled, it's something to keep in mind.)
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