If you have a broken link I would replace the timing chain. Chances are it is stretched and will continue to wear the timing chainrings. It is unlikely that a bike shop will sell you a few links, let alone have a new chain that is compatible. (I would not mix chain links unless joining them with quick links)
If you are set on keeping the chain, at least have the bike shop measure it for stretch. If it is stretched, replace it, or it will cost you much more down the road.
As for your original question, it is likely that the chainrings are consistent with the technology of the era your bike was built. 2006 was in the 9-10 speed era, so an 8 or 9 speed chain should be fine. The difference between an 8 and 9 speed chain is link width. This is important with regards to the spacing between the rear cluster cogs. The timing rings don't have adjacent rings and width is not a concern.
Enjoy your new bike!
Last edited by Alcanbrad; 05-17-15 at 04:54 AM.