What are you trying? Have you looked into the
Fundraising Toolkit? There's a lot of awesome ideas in there.
You also have a cool Assistant RD, a Senior Mentor, and some nearby teams worth reaching out to directly as well. Team 4159 is especially worth noting, since they're super close to you.
And do you mean "We just paid for our event and have $300 in the bank" or "We have $300 in the bank and an event to pay for"? If you're in the prior situation, you can probably go after a lot of in-kind donations, prototype only the most important mechanisms, and still probably get by. Otherwise, going after every grant and tech company the bay area has to offer is your best hope; finding something strong about your team (your rookie potential) to aggressively promote, and throw everything at the wall, that's probably your only shot.