$解:(1)对于y=0,△=(3-2m)^{2}-4m(m-2)=-4m+9\gt 0,m\lt \frac {9}{4}$
$二次方程,则m≠0,∴m\lt \frac {9}{4}且m≠0$
$(2)代入P坐标得m+3-2m+m-2=1,成立,∴在$
$(3)代入m=1,y=x^{2}+x-1=(x+\frac {1}{2})^{2}-\frac {5}{4}$
$顶点(-\frac {1}{2},-\frac {5}{4})$,对称轴$x=-\frac {1}{2}$
$则P'(-2,1)$