Question 888820
google "vertex and point"
You will get many ways to do it.

y=a(x-h)^2+k
where (h,k) is the vertex, substitute for x,y,h and k 

3=a(-1-2)^2-4
3=9a-4
7=9a
a=7/9
solve for a

Substituting into the original again for a and the vertex 

y=7/9(x-2)^2-4
Good so far

y = 7/9x^2-28/9x-8/9
Don't give up 53 is young.