Hello, there isnt any law which specifically mentions that the pre marriage promise needs to be delivered because marriage is not considered as a contractual agreement in the Hindu law. However if the mutual understanding between you and your wife formed the basis of the marriage, you can file a case for divorce on that ground alone. However, i suggest that you both mutually agree and file a divorce if you both want it. With regard to Psoriasis, as per the report there are 10% chances, this isnt relevant for you as much as the understanding between both of you was on the ground that she will not bear child from her womb but from a borrowed egg, You can persuade her to do so negating the report as given by the National Psoriasis Agency.
Chances for getting compensation in such cases are less. Further even if you both are not staying together, your divorce case cannot be filed before January, 2015. since the law provides that divorce can be filed only after expiry of one year of the marriage.
I suggest you speak with your wife and persuade her not to bear child from her egg, showing her the ill effects of the disease. Go to a Family consultant if required.