The only person I know which may could co-sponser for me is my sister, how can I convince her to do it? When she signs the forms what is she agreeing to do? Is she accepting the responsiblility to care for that person the rest of her life or just until she becomes a USA citizen? I need some way to be able to convince her that this won't cause a problem for her later on. Please help me someone!

warmthoughts,
you really want to get a joint sponsor who is not gonna give you a hard time cause you are gonna need some papers from him/her.
the responsibilities of the co-sponsor are the same as the responsibilities of the main sponsor which is you.
both will be financially responsible for the sponsored person and this will be till he/she gets U.S. citizenship or till the aplication is dropped (denied or he/she leaves the country). please note that the responsibility of the sponsor will not go in case of a divorce.
The main idea is that the sponsored person will not go on means tested benefits (such as welfare and others) before he/she becomes a citizen and if the sponsored does end up on welfare, you guys are financially liable to pay it back.
good luck

It's been reported in this community that such suits have indeed been successful.

warmthoughts,

Your best approach to immigration and marriage is to postpone both until you have a job or jobs providing sufficient income so that you can support your own family.

Yodrak