i want to create a only one coupon code and it should work something like

if subtotal is less than 500 , than 50 discount and if subtotal is more than 500 than 100 discount.

@Amasty posted here Multiple actions on shopping cart price rule : to create 2 different coupons with same coupon codes

but i want to create some 100 coupon codes and those coupon codes should according to above rule

this extension supports what i need, but only for 1 coupon code for one time : http://www.magentocommerce.com/magento-connect/tiered-coupons.html

please help me to find solution.....

thanks in advance.