It is very hard to delete the backups.. just try again.
Use a different method.. try Q16 here. http://pondini.org/TM/FAQ.html
But you should read all the FAQ that deal with restore,, 14-17
And if you really have wiped the backup, no, I don't think restore of the data is possible.. but don't jump until you check what is really on the TC. If you started a new backup, it will not overwrite the original data, as I understand it.. the new hard disk will force TM to create a new backup.. unless you did something weird.