by how much did the temp change before the dinosaurs were extinct up to the point?

Answer 1

Unfortunately, the reality is not nearly as exciting as Eugene N's answer.
Stable isotope data indicate that ocean temperatures about 100 Ma were 3-5 C warmer than current temperatures and in general the Cretaceous Earth was much warmer than it is now.
See link below.

Answer 2

By a few thousand degrees when they were wiped out by he asteroid that landed around the Yucatan Peninsula.