For a temp fix, just mic the violin. If you don't understand that concept, it means place a high quality mic on the stand right near the violin. Often times a drummer will mic the bass drum or snare or whatever if they aren't quite loud enough coming thru the amp(s).

This means you won't be dancing around the stage but it could easily solve your lack of volume. If you're singing already, I assume you have a mic on a stand you use, if you play and sing at the same time, you might need 2 mics, but if you play, sing, play, sing, you could easily just use the one mic for both jobs.