i am in usa for last 2 months for doing my undergraduate . but embassy due to their mistakes gave me visas for 2 years only. i colud not change it as it was chrisrtmas time and had to flt soon after that. now i am thinking to go to communiy college for my 45 credits hours. so i need to change my i-20 too. question is that i have heard that i cant go home when i am studying in community college as white returning back immigration officer could send me back . is that true or not.
d o i need to go to nepal for visa extenion.

and another qusestion , i have my american uncle , who want to sponser me . if he sponser my expenses what benefits will i get. am i allowed to work more than 20 legally or ant advantages
need suggestions

Dude you are screwed..

It should not matter what is say in your visa. Your I-90 should have DS written which means you are legal for duration of your study. As long as you go to college and maintain your status and maintain your G.P.A. you should not have a problem. As far as Immigration Officer they can send you back if they are not satisfy with your documents whether you are in University or Community College. OR they can simply not authorize for you to enter into United States. Good luck

For the first question, you dont need a valid visa in order for you to stay in america. Valid visa is simply states that you can travel to the country. As long as you 1-20 IS VALID you are fine. however if u return to you native country and the visa is expired then you have to renew your visa.
I dont know much about the sponsership....

dude,
Don't ya worry about that. You would be fine until your visa supports your duration of study. The best thing you can do now is to talk to your international advisor about it. Well if you return to NEPAL within your visa duration, then you don't have a problem. After your visa duration, you just need to show your I-20 and letter from your international advisor mentioning that you are studying over there in community college. They should let ya enter U.S.