Extra Suites will do that for you. Youc an download it from here: http://www.kanzu.com/
Its $10 shareware.
It can also tell you the color of the pixel under the cursor.
Theres plenty of examples with the download. I coded a quick test that closed the AH window for me:
Code:
tell application "Extra Suites" to ES move mouse {2465, 681}
tell application "World of Warcraft" to activate
tell application "Extra Suites" to ES click mouse
Of course your coordinates will not be the same as mine. There is also an example that shows you how to get the cordinates of the mouse.
Code:
tell application "Extra Suites" to ES mouse location
The result is the coordinates. The easy way to get the coordinates for a place to click in WoW, is to make a new applescript with the above command and then shift to WoW, place the mouse where you want it, alt-tab back to Script Editor and do the run command via keyboard (apple-r).