If my roku device is offline and lost the remote control how do I connect the device to my roku remote app
You can't. You need a remote. Did your Roku device suddenly stop connecting to your Wi-Fi or are you trying to connect it to a new network?
It just suddenly stopped working! I haven't had the remote in over 6months
What's the model number of your Roku that should be written on it somewhere? Also, who is your ISP? There's known issues with Comcast/Xfinity and Cox making changes to customer's Wi-Fi settings.