The two tamas have to be the same age to get the maximum points. You can get up to 300 points if the two tamas are good friends, but only 30 points if they are not the same age too.
You can use batteries marked AG13 or 357A or A76. I found some at Target, Wal-Mart probably has them too, but they are kinda expensive. The best way to get some is on EBay. I recently bought 30 batteries for 5 dollars, including shipping!!!
Kid Shamrock