Sounds like you had a Yakima roof rack system that was mounted to the factory side rails (the 2 bars that run front o back of the roof top on both the drivers side and passenger side) on the Volvo V40. So the issue is that you now probably don't have any kind of factory rails or factory rack on your 2007 Volvo S40. So you probably need to go with the Yakima Q Tower car rack system for properly configuring a 2007 Volvo S40 roof rack that you can then attach your bike carriers to.
You need a set of 4
Yakima Q Towers, 2 pairs of
Yakima Q102 clips and a pair of 58 inch length Yakima crossbars. You should measure your current crossbars because they likely are only 48 inch length bars, as this is the length recommended for your previous Volvo V40 model. If you do need the longer 58 inch bars then you'll want to just go with the complete
Yakima Q Tower roof rack system package.