Here is a heater for a breeding tank, and even larger tanks if you want. Set the temperature on it to about 84.
[ame="http://www.amazon.com/Hydor-THEO-Submersible-Aquarium-Heater/dp/B0006JLPFY/ref=sr_1_4?ie=UTF8&qid=1297178240&sr=8-4"]Amazon.com: Hydor THEO Submersible Aquarium Heater 150W UL: Kitchen & Dining[/ame]
The sponge filter is needed, because your fry need extremely clean water in order to survive. They also can't have a lot of water movement, which is why sponge filters work great.
This is the setup I have and it works excellent.
[ame="http://www.amazon.com/JW-Pet-Company-Fusion-Aquarium/dp/B0018CFMUW/ref=sr_1_3?s=home-garden&ie=UTF8&qid=1297178387&sr=1-3"]Amazon.com: JW Pet Company Fusion Air Pump 200 Aquarium Air Pump: Home & Garden[/ame]
Aquarium Biochemical Sponge Filter Fish Tank Air Pump - eBay (item 310271100226 end time Feb-13-11 00:12:17 PST)
This is basically what I have and it works excellent. The sponge filter each can be removed so you have good bacteria on one, while you rinse the other one off, so your tank stays cycled. That air pump is almost silent as well, it works great. As for water conditioner, good that you use it. May I also recommend indian almond leaves if your breeding. They induce spawning, and they are great bubble nest makers. My male builds his bubble nest under them all the time, he won't anywhere else. Good luck.
If you need help with them mating, ask someone else. I had trouble with mine, because I didn't condition them or introduce them properly. This is a must if you want them to spawn. As for betta care and stuff, I am pretty good with that. I might also recommend this siphon for changing your water. It makes it a breeze.
[ame="http://www.amazon.com/biOrb-822728000250-Cleaner-Pump/dp/B000KHZ0X0/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1297178665&sr=1-2"]Amazon.com: biOrb Cleaner Pump: Home & Garden[/ame]
Just don't suck up gravel with it, I did and it broke. I bought one on eBay which is basically the same thing.