How to match angle of other object

I am trying to get the arch in the following link to match the angle of the rest of that window area. I have tried everything I could think of in order to get that thing to align right. Any suggestions?

http://www.hlgaming.com/images/news/gtfc/change_angle.JPGhttp://www.hlgaming.com/images/news/gtfc/change_angle.JPG

With the selection tool and the solids selected, click on it twice, so that you get the 'pull' option (the one after 'rotate')- it should look like that image, but with only 4 small white boxes instead of 6- and drag the top box to the left.

Some images in this post have been automatically down-sized, click on them to view the full sized versions:

you should probably listen to Lep, he's the smart one.

But.. What i would do here is grab vertices and pull em to where the diagonal line is on the grid, like so.

Nice diagram there bobv. I've been in this situation before and leps method works the best.

Thank you very much.