Wah Wah Effect Question

Is there any way to make the frequency on the wah wah go over 4, or do I need to get another vst plugin that can do this?

You could change the sample rate of the track before applying the Wah Wah effect, then change the sample rate back.

Example: If the sample rate of the track is 44100 Hz, from the track dropdown menu, change the sample rate to 22050 Hz (http://manual.audacityteam.org/man/audio_track_dropdown_menu.html#rate). That will make the track play at half speed. If, for example, you want the Wah speed to be 6 Hz, apply the Wah Wah effect with the speed set to 3 Hz. Then change the track sample rate back to 44100 Hz.