My Kia Rio Cinco seems to make a clunking sound.

My Kia Rio Cinco seems to make a clunking sound-that has gotten worse-from beneath the front right end whenever I slow down and step on the brakes. I did have the brakes repaired some months ago, but could that be a damaged caliper other part? Also could a worn axle or ball joint be making that sound as I did have trouble with those in the past that caused that kind of clunking? Finally, do you think the car is allright to drive at highway speeds going longer distances like 50 miles, or should I not risk doing that just driving in the small town where I live until I find out what it is? Dan