Steverob---I got to thinking some more about your situation. You tell us that her parents are angry with her for not wanting to be more than friends with you. So...think about this (I'm sure you in all likelihood have) suppose she did go back to you only because of parental pressure. Would you want her back under those circumstances? She would only be doing it to either please them or avoid further wrath. Do you really think that your relationship would stand a chance of succeeding in that case?
Our daughter is 23 now and in high school she dated a couple of nice boys. However, the relationships didn't last---nor did we expect them to. We talked to her about the breakups---asked what happened and then let it be. I'm sure you're a nice guy and your ex's parents like you. That said, it's very wrong of them to get involved with this. If they do say something to you like "we've talked to her and told her she was wrong to breakup with you and told her to take you back.", find the strength to tell them that you appreciate that they like you but this is between you and the ex.