How can I modify my custody order in Arizona. The mother of my children moved back here from Virginia and is not allowing me to see my kids.

My divorce in Arizona occurred in December of 2011. The mother of my 2 boys lived in West Virginia at the time of the divorce. She moved there in summer of 2011 with the boys for employment. She moved back in April of 2012. She drove from West Virginia to Arizona supposedly for a vacation and also for my time with the kids for spring break. After my week with them, I found out that she had moved them all back to Arizona. She thinks I should pay 25% of the drive from West Virginia to Arizona even though it was a relocation and she was with my boys and her two girls. Is that so? Also, after I had the boys for the summer (as stated in the divorce decree) she now will not let me see them until the next scheduled visitation in December even though I am now only 30 minutes away from them. Is there anything I can do to modify the custody order? I read I have to wait a year after the divorce but it seems unfair I should have to wait until December to see my boys. We are all in Arizona in Mari