Sorhor,
That's a very serious question and it depends upon the resources of the graduate chapter as well as the undergraduate chapter. For example, I know that my grad chapter sponsors three undergraduate chapters and we have provided a lot of financial assistance to all three. However, one of the undergraduate chapters (George Mason) received funds from their school's greek affairs because they were one of the chapters that complied with the guidelines and procedures of the school.
When I was an undergraduate in the big 80s we used to make a nice amount from getting folks to sign up for credit card - it was easy to do but I don't know if your school will allow you to participate in that type of fundraiser because so many college students are in great debt because of good old mastercard and visa. Hey, you can also distribute phone books for Verizon that sometimes brings in a lot of revenues. Sometimes the local Pepsi and Coke companies work with the sororities and fraternites during different campus events.
I hope this helps!
Serioussigma22