Can any one tell me where can I buy a 2007 headlight unit .Its the left hand side passenger one .Will other models fit it .can I buy a hallengon and swap my xenon bits out .

 

If you install a halogen on one side and have a xenon on the other you will have a permanent bulb failure low beam warning. (because of the two different types of bulbs)

 

Google for Volvo 31383192 - that's the PN for the C70 xenon composite headlight (right/passenger side on a US/left hand drive car). They run about $850 new at a Volvo dealer store in the US and about $300 used (car-parts.com will search yards). Not sure if you are in the US or not... the part for the left/drivers side is 31383191. Its the same part for 2006 to 2010 C70s with HIDs.