Here is a good source for help with spay/neutering.
http://www.lovethatcat.com/spayneuter.html
Also, call local rescue organizations to ask them if they can help with the cost as well as with finding homes for the cats you do not want to keep. It is absolutely necessary to have your animals spayed and neutered. There are plenty of homeless cats out there needing homes without breeding more.
There is no quick solution to this - you need to separate them. You are risking serious injuries to one or both if you do not. Put momma and her babies in your bedroom and keep the door closed. Or vice versa.
edited to add: The babies MUST be at least 10 weeks old to be properly socialized and ready to leave their mother and litter mates. Please do not try to separate them before this as it will lead to all kinds of behavioral problems.