If we are already level 50 how can we get the new vampire or werewolf perks? Is there going to be an increase in level cap?

I hope so too

the level cap is actually 81, an i imagine the vamp and wolf perks will have skills associated with them to earn perk points

They do. I've seen the perk tree.

But I believe the perks are earned by performing actions not by spending perk points or leveling up.

Can't refind the image. Oh well maybe you are right. But wouln't that mean there is no choice over the perks you get?

The perks would also be free and you could get all of them by fulfilling the requirements. It also solves problems like "what if we're already high level with no perks to spend" or what if we get cured. What would happen to perks we spent? And besides what skill would be associated with the vampire or a werewolf? Having werewolf/vampire perks function just like normal perks doen't work to well.
Having them tracked independently however works much better.

they'll probably be like the ebony blade where you do these thing to level it up
and you can get different perks

That's what I'm like with my 81. If we got no more perks I'd be screwed.

Really? because my Nord isn't leveling up much at all & I've been leveling my one-handed & archery quite a bit.

This would make the most sense.

50 is the soft cap after this it takes a lot more effort to level up, but shortly before maxing out every skill you'll hit the cap of 81.