I've played at a Jewish wedding and also at folk dancing. I have 3 books 2 are like fake books related to Israeli folk dancing and one is a Yiddish song book. I use a 2 beat mostly country for styles and that seems to work for most of the upbeat type songs. The wedding I played the piano.
I was also just in a production of Fiddler on the Roof in the spring at a local university (I played the Rabbi) so I was playing songs from the show as well.
You could stop at a music store and see if they have any Jewish or Israeli music. There are a lot of books out there. If you can't find anything I can send you some of what I have that might get you started. I can write down which styles I use for each song. There are also numerous Midi files on the web where the music can be printed from Midi.
L'Shanah Tovah - Have a Sweet and Happy New Year!
- Brian