Getting ready to go to court for custody battle?

well right now i have a court date but every-time it get close to my court date get reschedule.first was due to weather this time it because she gave birth to a baby girl.i've been raising my son since they one but my son went to visit with her in 08 and never came back so that the reason i'm trying to get custody .i was allowed to visit with my son for 3 days for christmas .within the three days All my son was saying is that he hate his mom and don't want to go back.come to find out the dude she just had the baby for has a record ranging in burglary of 2nd degree been arrested 6 times for drugs and a resent arrest 2 mth ago for having 50 pounds of marijuana in his car and invading arrest for 6 weeks. i have all medical records with every visit shots when he was with me. and a letter from the day care when he attended,is there anything else i'm missing i'm located in austin tx and i have to go to court in Oklahoma for court hearing .my background is clean currently work at the as a supervisor in a juvenile detention center where i see what happens to kids that don;t have the proper role models in there life i seen kids from ages 13 to 16 facing any where from 0 to life. and i don't want that for my son.can anyone give me any advice