Replaced battery in remote key and now won't unlock/lock car

Hi,

I have a 2008 535i that indicated (on the IP) that my key remote was running out of charge/discharging. I placed the remote in the ignition lock while driving long distances to keep it charged (doing this for several weeks) , but still continued getting the message that the key was discharged/discharging when I recently tried to start my car without the key in the ignition lock. I am also having trouble unlocking/locking my car with the remote, in general. Comfort access hasn't worked in a while.

Looked in the manual to see how to replace the battery, which I did replace, but now, my remote will not lock/unlock the doors whatsoever, although the car does start up without the key in the ignition lock.
Called my BMW dealer who advised me it would cost $140 to reprogram the remote.

Was wondering if there was any way to program it on my own?

Thanks

The battery in the fob does not get recharged, placing it closer allows it to work since it doesn't have to broadcast as far with as much power, extending the battery life. Don't know about reprogramming, will be interested to hear myself.