The max temp for your CPU is 95C. At that temp, you will get a third degree burn from touching it. However, the CPU would probably produce a lot of erratic behavior or burn up before you reached 95C.
You said your temp is 58C. Is that at idle, I.E. no programs open, only desktop and whatever monitoring program your using, or under stress I.E. right after gaming or while running Prime95 or 3DMark? This is important. If 58C is your idle temp, then that's too high. If it's your temp under stress, then I'd say it's a little high, but not much. What kind of HSF do you have? I dropped both the idle and stress temps by 4C on my 1Gig TBird just by getting "a real HSF" and using Arctic Silver...makes a real difference. More info please.