Writers question cont. from last question?

ok I have a publisher who wants my mcript and the illustrations. i couldn't have asked for more, they already sent a contract to me and i just have to review it and request a actual copy to sign. I have never done this before so here are a few things that i am not sure about....they offered me nothing as an advance but also i would owe nothing if the book did badly. the first 2000 copies i would make 8%. after that it goes up to 25% and then when i reach 6000 copies sold I will make 50%. its a 7 year contract. also i am not sure but it sounds like they want to make it a soft cover and sell it for 24.95?! I think that's way to high. but i am hoping it was a sample number thrown in there on the sample contract. but it is something to address. I have no idea what i am doing, How do i get ertive and ask for more? and get the book in hard cover? and should i even do that? i don't want them to turn around and say forget it we change our minds. help! any info would be great! oh by the way the name of the company is publish america.