Replying to Neighbor keeps parking her car infront of our house....

So myself and a few friends moved into a house in Park City and it's pretty much just on street parking. 4 of us live in the house and we all have cars. We are able to park all 4 cars in front of our house when it's only us parking there. However, one of the chicks who lives across the street parks in front of our house some times, and it's getting pretty annoying. Today I guess one of my roommates put a note on the car politely saying, "hey would you mind not parking here because we really need these parking spaces, ect." Not the exact words but it wasn't a rude note or anything like that. We had previously put up some no parking signs that we got from Walmart, and I guess they had been all ripped down shortly after my roommate put the note on her car and after the car was moved (No one saw this happen, we are just assuming it was her). And what's really annoying is that they have a big "No Parking/Violators will be towed" sign at their place. So they obviously don't want people parking in front of their house, but this chick feels that it's perfectly fine to park in front of someone elses house? And then this bitch goes and rips down our signs? So I mean, is she technically allowed to park in front of our house since we don't have real permits/signs? And if so, is there a way to acquire these permits? I mean even if we did get permits and all, it's not like anyone would really be monitoring the street anyways.vWe are going to talk to this chick and ask her nicely in person to not park in front of our house anymore, but I'd just like to know if she is technically allowed to park in front of our house or not. Basically we don't want to start shit with our neighbors, but also don't want a constant battle going on over parking.