Your 1998 ZJ LA360 should have the 136A alternator from the factory - it's the only part listed for that year in my catalogue. You should be able to go up to 160A - I've posted lists of potential donors for Nippondensos going that high.
You should be able to do the job yourself - it's not terribly difficult. Worst case, pillage around in your chapter for someone willing to teach you for brats & beer (my usual fee is assessed in pizza and Pepsi, but that's just me. I don't care for brats, I can stand beer here in the States.) It will probably take you all of an hour - two at the outside - barring complications.
When it comes to mechanics, there are three I've trusted. My granddad died a few years back, "Dr. Doug" is retired by now, and I'm the only one of the three out here in CA anyhow. I was taking mechanic's classes a few years back to get myself certified, and I've seen what has been going into these schools - and what's coming out of them. They're relying too much on OBD for my comfort - I've run into cases where OBD was wrong (and it's a horrible specific troubleshooter anyhow.)
"recon" (sic - reckon)(tm) "hihgly"(tm) "seceed"(tm)
"Outback AIDS - Alcohol-Induced Dizzy Spells"