Bid two hearts.
You are light for this (according to most experts), but you have two good suits and should risk the overbid in order to describe your hand at the lowest possible level. "If not now, when?" once said a great sage.
Your immediate two-heart bid allowed you to show both suits below the level of three notrump. Had you responded two diamonds, partner would have rebid two spades and you would bid three hearts. If partner next rebid three notrump, how would you know wether to pass or to bid on? Suppose he held four diamonds and two clubs?
two hearts = 10
two diamonds = 3
Bridge Today, Sep-Oct 1993, p. 8