What could I do to stop getting pissed off because my anti virus subscription has expired?

My parents bought me an brand new HP Desktop on thanksgiving day to replace my old crappy 2001 dell dimension desktop. The new computer came with Windows 7 and it has a 2 month subscription to norton internet security 2009 version, norton internet security works very good because it protects me from viruses and spyware. The subscription is expiring tommorow which means if i don't buy another norton anti virus and put in that means i can't use my computer because viruses will get in. My parents especially my mother is so stucked and tight on money and budget right now which means i might have to wait until friday for them to buy it. I need my computer so i could do studying and some personal stuffs on the internet and facebook. I'm really upset because my mom wouldn't buy it for me today because she didn't have any money, I really made her cry because of my temper.I do have another computer which is my laptop but i spend more time on my desktop because it's convienant and because i'm scared of crashing my laptop due to overheating. I don't trust freeware anti viruses because nothing that's free is good because my uncles uses a free anti virus and when he got infected it didn't help him it just stood there, he used avast anti virus when that happened. My family is getting tired of me and they want to get rid of me. What could I do about my anti virus subscription ?? What could i do to be able to use my computer starting tommorow ??? Can anyone please help me out ???