To help you to get some actors for your movie, you're going to need some Casting Directors. Casting Directors are the people who help pick out people to act in your movie. The Casting Directors hold auditions to get actors to act out a snippet of the script and the person who does it best gets picked for the movie.

Where do I get actors?

One of the best places to announce auditions, is of course institutions like drama/theater schools. Also use online community forums like IMDB Pro.

Drama students can often be convinced to do a movie very cheap or for free — especially if it's their first and it's a low budget film.