No one can apply for naturalisation unless they have settled status in UK.
Now you have to apply for settlement which is known as "indefinite leave to remain" and in short ILR. You will have to apply on form SET(M). You must apply before your current visa expires on 30/03/2012. If you go even one single day over your visa expiry date, you will not be able to apply for ILR and you will not even be able to apply for another FLR(M) either. You can send your application on or after 02/03/2012.
Now you might find this next bit of information strange, but thats the way rules are drawn. Once your SET(M) is granted and you get your passport stamped with "indefinite leave to remain" or ILR in short, you can apply for naturalisation on the same day. Being married to a British citizen you do not need to wait another 12 months after ILR to apply for naturalisation.
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