I would say yes, there wouldnt be any harm at all in adding new yeast seeing as the original is almost deffinately dead. I made the same mistake just two days ago.
I could be wrong, this is only assumption and a novice brewer saying this, but i dont think it matters what yeast you use next, providing obviously that its acceptable for that style of beer you are brewing.
I have seen comments about making sure to use the same yeast strain as the original but if the yeast has died already without being able to work its magic i suspect a different yeast wouldnt be to the beers detrement?
Please correct me if this theory is incorrect.