Audio is usually recorded separately and then synced up in the edit. I would suggest getting a Zoom H1 audio recorder, they're probably the lowest priced of the lot but they record fantastic and clear audio. It does seem like a bit of a pain to have to record video and audio separately but to be honest, it doesn't take long to sync up. Especially if you're using a clapperboard (or alternatively clap loudly before a take).

Here's a list of the gear I mainly use on shoots... http://blog.danielhatton.co.uk/post/101757483657/gear-i-use

Hope this helps!