Have you tried removing the drive and mounting it (through Truecrypt) on another machine?
Just use the...
System -> Mount Without Pre-Boot Authentication
...option and enter the password for the encrypted volume and it should mount like a regular Truecrypt volume. This would allow you to verify that the data is accessible.
Alternatively, you can use the Rescue Disk to try to decrypt the laptop drive. From the Rescue Disk, select...
Repair Options -> Permanently decrypt system partition/drive
...and enter your password. This will take some time to complete and will leave the drive decrypted. This would at least let you get in to fix things. You could then re-encrypt the drive at a later date.
If it will not boot after being decrypted, you may need to use the Rescue Disk to restore the original system boot loader. You can do this in the Rescue Disk with...
Repair Options > Restore original system loader
...However this should ONLY be done as a last resort and only after the drive is decrypted.
If none of this works, your best bet is to reinstall. This is, after all, the intention of full disk encryption: to protect the contained data from access.