There is lots of controversy and differing opinions about size and
location of swap.
If you need more swap, you can
First, back up critical data or be at peace with the possibility of
losing it, since you'll be messing with partitions. Then:
Resize another partition to make it smaller--you can do this with
parted or qtparted. Then delete and recreate your swap partition
using the newly available space. You'll need to turn off your swap
space with swapoff first, then turn it back on with swapon.
Or you can create a swapfile with mkswap on an existing partition, and
activate it as swap space with swapon.
see man parted, man mkswap, man swapon, man swapoff for more info.