Yes you can create a swap partition on another drive. You can even create a file and format the file with the swap format and mount the file.
# mkswap -v 1 (file or partition)
# swapon -p -1 (file or partition)
(you can use dd to create a file, or typical partitioning methods)
(a file is likely less efficient, but it's the least risky to make and use as needed)
# swapon -s
(shows usage stats)
# swapoff (file or partition)
(like umount but for swap)
You should probably find out what exactly is eating your RAM up. And address that to remove the need for the swap. Ideally swap should be it's own device for maximum performance. If not, then somewhere in the middle of the disc to ensure that the read heads are at worse 50% away from using it.