( x - h ) ^ 2 = 4 a ( y - k ) , where (h,k) will be the vertex
thus:
( x - [ -2 ] ) ^ 2 = - 4 [ 2 ] ( y - [ 0.5] )
therefore your vertex will be: (-2,0.5)
as this is a concave down parabola, focus will be: (-2,0.5-2)
THEREFORE your focus will be: (-2,-1.5)