I posted a link to an article that explains the transition. If you had read that then you would have the new address. You can also get it by looking up REP on etherscan. You can also lookup your address in etherscan to quickly check if your REP is at the address.
If you want to know how to follow a token thats going to depend on what ethereum client you are using. I have never used Exodus wallet but a quick google says that you need to rescan your balances:
http://support.exodus.io/knowledge_base/topics/my-balance-is-not-correctIf that doesn't work and your REP is not at your address on etherscan then you have ruled out the funds being at your address and you can move on to bugging bittrex. Etherscan has a tab for viewing all of the ERC20 token transactions, I would start by identifying the transaction of the old token contract or new where you sent the funds to the exchange address and include that in your support ticket. If there is no transaction and your funds are on the old REP contract and not on the new one you need to contract the Augur developers and see if they can help you: augur.net has a slack invite link or you could just make a reddit post in /r/augur. I doubt that this would be your problem, its most likeley that your funds are just not being shown by exodus. If it is exodus then you could contact their support or try and transfer your keys to a different client like myetherwallet.com mist or parity depending on the format of the keys, I dont know if its a regular json or if its a seed since I dont use exodus.