Freedom said exactly what I was thinking. When ever you decide to get another pet....it is not to take the place of the one that has passed. But as sirrahved said...it fills the hole in your heart.
When our DJ dog passed it was only three weeks before we got another dog. That was because the house seemed so empty without DJ. Zoee didn't replace DJ, they are two completely different dogs, with different personalities.
Now when (and I hope this is a LONG ways away) Taz leaves me, I will just see how I feel at that time and make my decisions then.
So it's really how you are feeling. Do not feel guilty if you get another cat right away. If it will make you feel better, then go for it. Cole will understand you've got lots of love to share.