You'd be entitled to child tax credit, but not working tax credit, from what I can gather.
Do you work at all - even just demonstrating a few hours per week? You could possibly see about things like income support. Universities vary wildly in terms of the help they offer student parents so go and see your student support section, they will be able to advise you of what is available from the Uni and whether you qualify/how to apply. Regarding full time vs part time places - if the help is substantial enough, you could always just take a full time place and not use every day. You would have to obviously do the financial calculations on that one.
I would visit the Citizen's Advice Bureau or Job Centre for benefits advice to make sure you're getting everything you're qualified for. You're going to need it all! Congratulations :-)