Only the first sentence sounds right. Either is not used the way it is used here.
The meaning of "either" that you want to use is "also; too; as well; to the same degree". Either is used as an adverb only after negative clauses coordinated by 'and', 'or', 'nor', or after negative subordinate clauses
He's not fond of parties, and I'm not either.
If you don't come, she won't come either.
And a better way to say the same thing is :
Wouldn't you like to know too ?
Won't you be interested in knowing as well ?