1. Maria is in the poor part of rivertown, her house is right in the middle. She will give you quest of restore maria's reputation.

2. I bought that branch from Mpenzak but the spell didnt work and the summoned demon killed Corrina and attacked me, i just killed it. It could be something wrong with that branch. Try to get one from the talking tree in Dark Forest (road to dark forest- NW form archers guild). Btw i found a book about mage Corrina who was killed by a demon, what a coincidence :>