Recover Vista after XP installation

Hi!

I have my HDD with Vista configured like this:

C: - Primary Partition (Vista)
D: - Extended Partition
E: - Extended Partition


Then I had a unallocated free space in my HDD and installed XP on it.
Now I can't see Windows Vista, because as I read XP overwrites the MBR
and Vista isn't recognized to boot.

I've tried all the ways I found on forums to resolve this but Vista
won't but no matter what I do.

In D: and E: extended partitions I have critical information and I want
to know if anyone know a way to save that data and even if I can restore
Vista to boot the data would be available?

Thanks in advance to any help...