How to specify period/time between two auto restore point created

I'm using Windows Vista Business and system restore help a lot by auto
setting or creating snapshots of system to let me restore if there's any
problem.

The problem lies in the restore point are created TOO FREQUENTLY and
EXCESSIVELY, which will result in a high HDD use even i'm running other
application. On desktop that wouldn't be a problem. Currently i'm using my
Laptop which has much more low speed HDD and the too frequent auto creation
of restore point really hurts the performance. My HDD indicator light falshes
nearly most of the time.

Any method or tweak to prolong the period between two succesive auto restore
point created?

Thanks for suggestion.