Hi Nicola, You need to look at the PCD (this is the bolt pattern & dimension), bolt/nut size, wheel offset & centre bore of the alloys plus whether your car can accept 15" alloys & if so what width.
1997 looks to have been a changeover date for Corolla models but as far as I can see looking at one site PCD is 4x100, bolt/nut is 12x1.50, centre bore is 54.1 & wheel offset of 45.
What wheel size & tyre size is currently on it? In order to keep the speedo correct if you change wheel size you have to also change tyre profile to compensate.
Also, if you do change you should inform your insurer & they may or may not vary your premium.