Well, the first obvious source for Baroque-style would be Baroque composers. Start listening to works from the early composers like Claudio Monteverdi, Girolamo Frescobaldi, Dieterich Buxtehude (he greatly infuenced Bach) to later masters like Antonio Vivaldi, Alessandro Scarlatti, Georg Philip Telemann, Giovanni Battista Pergolesi and, to me the two greatest, Georg Friedrich Handel and Johann Sebastian Bach.
Practicing things like the basso continuo parts of harpsichord/organ/piano pieces, arias and chorales will get you get going in no time. Remember to study the melodies too! Well-Tempered Clavier is highly recommended, I have also used it as study material.
That should keep you busy for a while. For the sheet music, check this site
International Music Score Library Project (IMSLP) Portal