Yes, you can have two 401k plans. I don't know whether you can roll a tIRA into a 401k, but I'd rather ask "why would you want to?" You almost certainly have more options for your own tIRA than for your 401k's.
What is your tIRA invested in? If it's a simple interest-earning account, I'd roll that into a tIRA at Vanguard in some index fund pronto.