be careful if you decide to get a male AND a female betta, if it's small tank and you only have one female in there...all the males "attention" will be focused on her and if she not ready to spawn when he thinks she should be, he might nip at her till he kills her i've also heard that when they do spawn they both can get pretty tore up
check out this site there's alot of good info http://www.bettatalk.com/
???also it does you no good to let your tank sit for a month, let it run for a day after you add water conditioner, to get the water settled and then you could either put fish in or try to fishless cycle see the article on this site...letting your tank sit for a month without an ammonia source will not accomplish anything :
a dwarf african frog (NOT AFRICAN CLAWED), a snail or maybe some ghost shrimp might make good friends for a betta in a small tank... better than another betta anyway IMO...ask around see what people suggest
good luck w/your new fish *thumbsupsmiley*