you can use the formula for rotation

x' = (x * cos A) - (y * sin A)

y' = (x * sin A) + (y * cos A)

Try these links also

1). http://www.codeproject.com/gdi/setworldtransform().asp - Using SetWorldTransform() to rotate basic shapes by any angle

2). http://www.codeproject.com/gdi/rotated_dc.asp - Rotate your graphics

Good Luck