You can create two swap partition there is no issue This can be done in two ways.
1)if you have free partitions left
2)if you dont have free partations left..
From your post i understand you dont have free partation left(bcz you created all 4 partations as primary partations)
When you dont have free partations left you can try creating swap using free space available in any of the mention 4 partitions
please follow this link it will show how to create swap file and use it for swap related activity
The Linux Juggernaut: Swap Management - II