I went to trade in my car on the weekend and was given a new car without

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loan approved? I went to trade in my car at Tom Jumper Chevrolet USA- world's largest Chevy Retailer on April 12, 2008 which was on the weekend. I signed all of the paperwork thinking the loan had been approved. Afterwards I was told that the loan had not been approved due to it being a weekend and the banks are closed or don't do loans on the weekend which worried me a lot being that I was been given a BRAND NEW (only 12 miles on it) car to drive without an approved loan. I was then told by the finance manager that they would not let me drive off with the car if they weren't sure that the loan would get approved. Now it's April 21st and the loan still has not been approved but was told that one bank approved me but I may need a co-signer which I don't have. I asked what's taking so long and was told that they were "picking at things" (whatever that means) and was reassured that they will get the a loan approved. If the loan is not approved, what should I expect to pay for this NEW CAR?
Also, what happens to my trade-in like will I get it back or what if it has already been sold? Will I get my downpayment back? The 1st months payment on the new car is not due until the middle of May.
Will I have to pay a Pro-Rated amount for having the New Car for this amount of time?