Time Machine restore question, Need help!

BACKGROUND:
I am actually on my third iMac in one month (I have upgraded all the way to a 24" now). I have three folders on my time machine drive which is hooked to a 1TB external HD and respectively named iMac1, iMac2, iMac3, with iMac3 being the newest 24" folder. I just did a restore from a Time Machine backup on my brand new 24" at the start of OS X setup so I could have all my settings, programs, etc. be the same...the problem is, the restore that it implemented was from July 9, not the 21st so some things have changed.

PROBLEM:
Time machine will not read my older backups (so I can go back to a few hours ago and restore) because they are all in folder iMac2. I tried copying iMac2 to iMac3 (the newest folder), and it will not let me move files.

WHAT I NEED ANSWERED:
Long story short, I just want to move the files from my two older machines (iMac1 and iMac2) into the iMac3 folder to make them accessible to restore too.

Thanks for everyone's quick responses!

 

You cannot just copy manually, I tried that. Nothing can be copied, cut, pasted for moved from the backup folders.

I cannot mess anything up due to not having time machine hooked up at the moment so it cannot do a new backup. The only backup on there is the one I restored to from July 9th.