cooling systems

Hi guys. I'm after some advice regarding my 2002 Diesel Corsa. The problem came to light yesterday. The problem I have is my coolent is leaking into my drivers footwell. As you can imagine it causes my feet to get rather hot. I think it's coming in from under the heater on the left had side...

so my radiators leaking badly, its obvious i need a replacement, but i need to no if it matters what corsa radiator goes in. i own a 1994 Mreg corsa b 1.5d merit, and have found a radiator from a 1.0 petrol corsa b. i guess it will be the same mounts etc. but will everything be okay or are...