I've been using Win500 on my PRO-197 (sister model to yours, base instead of hand held) along with my subscription here at RadioReference. Not to make this a commercial, but it can't be much simpler. I fire up Win500, import from the site, select my country/state/county (in my case) and choose what I want to import and where I want to put it. After the first couple of times doing it I can now completely reprogram my scanner in about 15 minutes including three trunked systems and about 400 conventional freqs.
I also have ARC250, which is older than ARC500 and for a different scanner, but between the two I prefer Win500.