we have 

Step 

Find the distance AB in the x-coordinate

Step 

Find the distance AB in the y-coordinate

Step 

Find the coordinate of points C and D in the x-coordinate
Let
Cx------> x coordinate of point C
Dx------> x coordinate of point D
Ax------> x coordinate of point A


Step 

Find the coordinate of points C and D in the y-coordinate
Let
Cy------> y coordinate of point C
Dy------> y coordinate of point D
Ay------> y coordinate of point A


therefore
point 

point 

see the attached figure
the answer is
the coordinates are 
