MAGENTO - CREATE ONE COUPON CODE WITH MULTIPLES CONDITIONS

General information for the website: We sell food online
Description of requirements/features: Dear Developper,

My requirement is very simple but I have no Idea how to set it up.

I need to create a coupon code which offer:
10% when basket is lower than 2,000 THB
or
200 THB off when basket is higher than 2,000 THB

Coupon code must be WELCOME2YOU
valid only once per customer

My second requirement is about a voucher which generated automatically. I would like to modify the rule.
The coupon must be not applicable for the category ID 187.