Factions - Nightfall

Hello
I have Guild Wars Factions but if i get the next game - Nightfall - would i need another 'Game activation card'?

When you get nightfall, it will come with an activation key that you'll need to add to your current account in order to unlock nightfall on that account.

hmm, alrighty then, thank you very much

For more details, what you need to do is login to your account. At the character selection screen, you'll see a couple of buttons at the bottom of the screen (delete character, create character, and edit account). Hit edit account. From there, you'll have to option to enter a new cd key which will unlock NF and give you 2 additional character slots.