Here are couple of ways to do it:
Here is with Photomerge Scene Cleaner
Alternatively you can try downloading the trial of PSE11 which has content aware tool and many other kewl features. If you like it then at end of trial period just upgrade our PSE7 to it (there is different price for upgrade)..You can still have both PSE 7 amd 11 as these are different apps.
Hope it helps