Can you drive a '00 VW Jetta with 3 steel wheels and one alloy wheel?

I need to replace my spare and the auto salvage only has stock alloy wheels and no steel wheels. I am leaving on a 2,500 mile trip on Saturday and need to have a spare just in case I get a flate, a tire blows out, etc. All the wheels will be the same size (15x6). The alloy would actually be my spare tire. Could I drive with the alloy if I had to. How far could I drive on it?