finding y-coordinate of a 4-torsion point on elliptic curve

Question

I found the x-coordinate of my 4-torsion point on E: $y^2=x^3-3267x+45630$ given by $x=15\pm 36B$ with $B^2=-2$. My question here is how am I to find the y-coordinate of this 4-torsion point?