What am I entitled to???

I am currently on maternity leave and receiving maternity allowance, I ceased being self employed in January when I gave up work to have my second child, I have 2 children one at three and 1 at 5 months, I live with my partner in our mortgaged home. I would like to return to work on a part time employed basis (preferable 16hrs) and would like to know what benefits I would be entitled to if I did return and who to speak to about them, I'm at a complete loss please help!!!
Thanks