Going by past experience, the answers are:
1. Does it apply to quests as well ?
The bonus XP will apply to quests and mob kills, but the TP will only apply to mob kills.
2. When it says '150% more', does it mean 150% of the original xp, or the original xp + 150%? eg, if a quest is worth 100, then would the next xp be (quest x 150%) = 150XP, or is it (150%*quest)+quest = 250XP?
The bonus XP and TP will be in
addition to the normal amount of XP & TP received. Therefore, "150% more" means a total of 250%.
Perhaps a Mentor, Moderator or CM can confirm this but I've been playing since late 2008 and have seen enough of these type of events to know how they work.