Inbuilt - it's a Delco alternator. It's a lot easier (and less work) to just replace the alternator, since you'll have to take it out anyhow.
If you'd like, I've got an alternator ID guide on my website (in the San Jose Generator section,) so you can take a look. Specifically, it's a Delco CS unit, and is also used in quite a lot of Chevvies.
I don't know if he does international shipping, but I talked him into doing mail order for the US, and it's worth asking if you'd like a high-output unit.
5-90