You have 3 choices....
1. Replace your steelies with genuine Volvo RWD alloys such as the Aurega in the second post or the Galaxy's. or the standard 15 inch alloys off a standard LPT 940....
2, buy any of the FWD Volvo alloys in a 15 or 16 inch and use 20mm hubcentric spacers to reach correct fitment
3. do what i did and buy an aftermarket set of 17 inch alloys, The ones in the pic are Lenso Eagle 2 ET35 with a 20mm spacer