Both are correct. I too, am very busy. I am very busy too. Just you have to omit the comma from second sentence and place it in the first sentence as above.

Yes you can use both expressions

Both forms are used. You don't need the comma before too, although you can use it if you want. I am very busy too. Normal style I too am very busy. Formal style emphasizing the subject. While I'm at it, I might as well add the third variation. In American usage "too" can go after the verb. I am too very busy! This means... I am indeed very busy. It is used to emphasize that something is true.

"I too am very busy" incorrect.

Hi... "I am very busy too" is the correct sentence.