Piggy Back H-Briges

So I got me self some H- briges (L293B)
I got them working like a charm with some small motors.
But since I got the L293B not the L293D I do not have spike diodes.
My first question is, can I implement that function by just adding some diodes? Also, I have seen some circuits with capacitors between the motor and the Brige. Is this nessery and what caps should I use?
Finally, I also read something that you can link two Hbriges so the Ams are higher. Can somebody confirm that and tell me how to hook that up?