Two months behind on rent + other bills PA

[Amber Smith]

First time landlord here. Bought a property in Pennsylvania in September of last year, its a two unit. I am living in one and inherited a tenant in the other. She and her boyfriend had been there for a year and almost 10 months before I bought the property, so I wasn't expecting any problems. Within the first month of owning the property her boyfriend got arrested. She has been late on rent every month since then, but has always paid her rent by the 10th at the latest. Flash forward to January, and she kept giving excuses about late bills and rent, "cant get to bank, work shorted her check, overdid Christmas, etc". Its now February 1st, she owes a grand total of $1920.00. She claims she is moving out by the first of March. Can I give her a 10 day(?) notice to quit for Jan and Feb rent and all of the back bills owed? Or is it just for late rent exclusively? There is also a cosigner on the lease, should I contact them before giving any notice? Any advice would be great.  THANKS IN ADVANCE.