If IVR-only (a 1x0 PBX), you can use just a special “voice MODEM” card called X100P (or many of its clones, such as a Motorola SM56). Such sells for under US$20. But if you need to record a conversation between live parties, the person picking up a phone needs an interface. That requires a 1x1 PBX. (Asterisk is a PBX, no matter what )
You have two basic choices. If you still want to use X100P or clone, you’ll need a hardware IP phone, a software IP phone (soft phone), or an alalogue telephone adapter (ATA) plus your old analogue phone. A hard IP phone starts at US$100, an ATA starts at US$50.
Another choice is to use a special telephony card that includes both an FXO interface (for the line) and an FXS interface (for the analogue phone). This could be a Digium TDM400P (TDM11B has the minimum configuration you need) or a similar card from another vendor. This configuration costs about US$180 to US$220. Of course you can use a Digium card configured with just one FXO (about US$100) instead of an X100P. The quality is better.
I think most U.S. vendors ship to Canada directly. Or you can search the Web for a local vendor.