please help!

I have thick, long( half way down my back) and really curly hair. I like to wear it straight so I usually press it. The problem is is that I play sports during the school year so I usually sweat out my hair in a matter of days.

I don't know what to do with it. I would still like to wear my hair down, i just need a style that will last. Is there anything I can put in it to set it and prevent frizz (something like mousse)? Any suggestions would be great. Thanks!