Well, I suppose I'll start by saying "welcome!" not only to snape_potter, but to insanejournal and fanfiction.
No, I'm not the welcoming committee, and I'm not a mod here, but I think not enough people get welcomed and encouraged in these journals sometimes, and since you're posting in the middle of a fest here, this might just get lost in the shuffle... and I don't want you to think it's any reflection on you.
So, I just read your fic. Do you want an honest analysis or just the things I liked about it.
I will say this before anything else: you need a beta. Everyone does! Even those who have been writing for years need betas. Even those who write professionally need betas, and if anyone thinks they don't need a beta, they probably need a beta even more!
That's someone to read through, check for spag and britpick for you. 'Cause much like art, sometimes we get to close to our own works to see any flaws.
That being said, let me know if you'd like a full analysis. ^_^