Reboot into Clockworkmod recovery.
In CWM, advanced-> partition SD card.
Once the option is selected, you will be given options to choose the sizes for the sd-ext partition as 128,256,512,1024, 2048 ans so on. This will be the size of your first partition where apps are moved using a2sd,link2sd etc.
Now you will be given the option to select size of an optional /swap partition on the SD card. If you don’t want a swap partition then select 0.
The remaining space will be used for normal SD card usage. When you press ok, the recovery will do the rest for you. It may take a little time so be patient.