How can we prove our innocence?

I was working at a local convenience store and I got into the habit of playing scratch off lottery tickets. I was playing while I was on the clock and after my relief got there, I would clock out then buy my tickets for the day then go home and my fiance' and I would play them. Instead of cashing them in all at one time and spending the money possibly on more tickets, we would just save all of our winners and cash them in when our bills would come due. The employee that was my relief all of a sudden started playing lottery and also started having quite a bit of money and expensive property. I never thought anything of it until the corporate company came and said there was $20,000 worth of tickets stolen. I went and got my banbk statements printed showing where I was spending $50-$300 A DAY on tickets at the store alone. She told me while we were in jail that she stole the packs of tickets and that she knows I had nothing to do with it but she's saying the complete opposite to police.