Suzuki engines have always been, for the most part, small displacement, high rpm designs - I can't tell you what is normal for that particular vehicle, but it doesn't sound too far off (I'm assuming you have the 3 speed auto, without over drive) - I would not be too bothered by holding 60 mph for long periods, at least not from an engine longevity stand point - they're designed to produce their power higher in the rpm range.
No - a manual transmission won't solve the problem, it's not a problem, it's the way Suzuki built them.