Answer
Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, the Most Gracious, the Most Merciful.
All praise and thanks are due to Allah, and may the peace and blessings of Allah be upon His Messenger.
In this fatwa:
1- If you performed the obligatory Hajj of Islam previously, then you do not have to do anything.
2- If you did not perform Hajj before, then you should have stayed until you performed the obligatory Hajj.
You should hasten to do Hajj as soon as you can.
Elaborating more on this, the late Sheikh Ibn `Uthaymeen, a prominent Saudi Muslim scholar, (may Allah shower mercy on his soul), issued the following fatwa:
If the person who is doing tamattu` enters ihram then he decides, after `Umrah and before he enters ihram for Hajj, not to perform Hajj, then he does not have to do anything, unless he had made a vow.
If he made a vow to perform Hajj this year, then he has to fulfill his vow. If he did not make a vow, then there is no blame on him if he does not perform Hajj after doing `Umrah.
Allah Almighty kows best.
Excerpted with slight modifications from: www.islamqa.info