You can use the [scale] object. [scale 0 127 100 5000] would for instance take a number from 0 to 127 (your midi value) and scale it between 100 and 5000. If you want to change the range of the output values, use scale’s inlets for this.
Of course, you can also do it by simple mathematical calculations. Divide your midi number by 127. (giving you values from 0. to 1.), then multiply it with your desired upper frequency. For example:
[dial] > [/ 127.] > [* 5000.] > [cycle~]
Of course, one thing you need to accept with any of these methods is that you won’t be able to leave behind the "grid" of 7 bit resolution of the midi value. Even if you spread the values to range from 0 Hz to 10000 Hz, there will still be 128 distinct steps and not a continuous glissando, if you move your dial.