The greatest moment of dramatic irony I can think of between those two scenes occurs as Capulet is making these wedding plans with Paris without Juliet's consent:
I think she will be ruled
In all respects by me; nay, more, I doubt it not.
What makes this ironic is that he thinks he can get his kid to obey and to want the man he wants for her and for a reason she really doesn't care about (Tybalt's death). Capulet doesn't know that Juliet cares for none of this, she feels the exact opposite about all three of these issues.
Much of what happens in Act III, Scene 4 is ironic in this sense.
First of all, Juliet is crying a great deal. Her family is acting and talking as if she is crying for Tybalt. Instead, she is crying for Romeo, who killed Tybalt.
Second of all, her family starts to push her to marry Paris. Although they are doing this, we know that she is already married to Romeo. This gets to be even more ironic because we know that Juliet is alone in her room with Romeo at the time that her father is giving Paris permission to marry her.
Another example of irony is in Romeo's lament before Friar Laurence in Act III:
There is no world without Verona walls,/But Purgatory, torture, Hell itself./Hence banished is banished from the world./And world's exile is death. The "banished,"/Is death mistermed. III,iii17-21)
There are two instances of irony in Romeo's remarks. First, he states that it is Purgatory and Hell itself to be outside Verona when within the walls of the city he has been hated all his life by the Capulets, and he has committed an act of murder.
In another instance, Romeo declares that being banished is "torture and not mercy," but
...Heaven is here,/Where Juliet lives, (III,iii,29)
He thinks that if he could stay in Verona, he would be in "heaven," but he does not know yet that Juliet is so upset over Tybalt's death.