marrying a green card holder best option

[indian angel]

im presntly on B1/ B2 multiple entry for 10years visa ( valid for 6 months) ...im planning of getting married to my bf who is a green card holder for now...he will become an american citizen in two years ( march 2014) ...which is the best option for me....? should i wait for him to become an american citizen till 2014...? i know its illegal to enter the country with the intention of getting married with a tourist visa...
if my fiance applies for a fiance visa (k1) after he becomes a usa citizen in 2014 can i be with him in usa still maintaining my single status on the same tourist visa ? or will i have to wait in my home country ...? can i change my tourist visa to fiance visa while im single in the usa...how long can i stay with after getting my k1 visa...can i leave usa often as i want ?