Research: Ultrasonic from PC Card

Looking for ready made device or card to PC which allows sending ultrasonic pings through a pair of transducers in both directions. 1. Assuming that two transducers will be positioned watching each other. We should be able to generate a ultrasonic ping using one transducer and receive it by other. After analyzing signal, send the ultrasonic wave in opposite direction. 2. It must be possible to control ultrasonic wave (frequency, time). 3. Device should also be able to process wave received. 4. Unit cost is the major factor.