About American visa~~

Got in USA in October last year, gave me a six-month I-94, but I rode very slow, and now I want to apply for an extension, I do not know what that entailed. Please give me some advices.
Now there are several questions
1: I am a B2 holder, visa has expired (accurate to say that I was an expired visa is valid until the day before entry) is that expired visa can not apply for I-94 extension of it?
2: My passport expires in June of this year, it has apparently been set aside for a passport. The impact of extension of I-94?
3: I-94 extension through the mail? How long will it take? If you wait longer than the period of lawful stay how to do?
4: I want to change my new assport in Houston, for Chinese citizen it need wait for more than 40 days???
5: I am now very embarrassed, there is no return ticket, It was suggested that switch B2 into a F-1, but a friend said that in recent years, B-2 switch to F-1 looks like it is difficult