Backing up two macs
We have been backing up my MacBook air, and my wife's MacBook Pro to a 1 TB time capsule. My wife replaced her hard drive with a hard drive of the same size and restored it. Since then she receives a message that there's not enough memory on the time capsule to back up. In evaluating the time capsule, it appears that my backups are taking up 730 some gigabytes. I tried deleting old backup files using the finder, but it did not free up any space on the time capsule.
How can I free up space on my time capsule so that my wife can back up also?