Don't take the easy way out with stop leak. It could plug the leak but that stuff will be floating around the cooling system. With a turbo and AWD the cooling system needs to be fully up to scratch. If your lucky, it's a loose clamp but a heater core will mean lot$ of labour to r & r.
If you don't fix it yourself (I wouldn't) you could shop around for best price but someone who's done the job before would be cheaper in the long run. Not knowing where all the fasteners are and which wires to disconnect could cause more problems in the long run. A Volvo shop that's not on flate rate could be the best bet.
Thks. for the feedback. Just yesterday i noticed the floor boards (smell also) had coolant on them......yaaaay........I'm taking the car in tomorrow to see what exactly is going on. (heater core issue) I can get the parts fairly cheap from eeuroparts.com It's a reliable site;I have bought parts from this site before.