When you want to say that you, or someone else, has done the same as someone else, you use too, indeed.
However, in the negative, if you want to say they have not done something, just like someone else has not done it, you use either.
I enjoyed watching the game. I bet you guys enjoyed it too!
But:
The game was boring, I could not watch it till the end! I bet you guys could not either!
Alternatively, you can substitute neither for not either (thanks WS2):
The game was boring, I could not watch it till the end! I bet you guys could neither!
If you would use too in a negative sentence, it means something else:
I scored 1000 points in this game. I bet you cannot do it too!
Notice that now, I did score those points, and I am betting that someone else can not do it.
Better looking is, What he had just said—especially the last sentence—really enlightened me. The em-dashes indicate a break in the flow of the sentence, whereas the commas seem to be used appositively, which, while not incorrect, is not strong enough (it seems to me). Alternatively, parentheses [brackets in UK] could be used in place of em-dashes.
Best Answer
Yes, I think the first one is incorrect. 'You had told me' is the pluperfect (past perfect), and I suspect (though cannot be sure) that you do not need the pluperfect at this stage.
There are, however, circumstances in which the pluperfect could be used twice, such as if I say:
'Last Thursday, you told me John was going to Birmingham. However, he had earlier told me that he had done all the travelling he intended this month.'