This is based on the Natural Ranged Attack (Major) or (Greater) in RMFRP Character Law pg 71?
I would say you get one element unless you want to purchase the talent a second time. I could see giving a discount for the second one (half cost?) since it's not twice as useful.
It's ambiguous how much activity is required to make an attack using the talent. Personally, I would make it 60-100%, same as a melee attack. Not 30-60% as for a missile attack because those assume reload time. I would not allow simultaneous attacks (e.g. take the talent twice to dual wield blasting simultaneously with each hand) but if you had enough activity for two separate attacks (e.g. Haste) I would allow that.
This is definitely subject to the GM's ruling though, since it's not stated. And talents in general should always be considered subject to the GM's approval in any case.