Connect Apple Wireless Keyboard with my MBP
Default bluetooth of MBP 2011 does not support Bluetooth 4.0 so not compatible with the latest Apple Wireless Keyboard (i.e. 3rd gen with two batteries). No hardware upgrade possible. 

External USB 4.0 adapter possible. 
Similar problem in the thread Early 2009 iMac upgrading to Bluetooth 4.0.
This dongle IOGEAR GBU521 Bluetooth 4.0 Micro Adapter is one possibility as discussed Using unsupported Bluetooth 4.0 USB dongle with OS X.
The dongle is not shipped to Finland. 
The only option is to order a corresponding item from China, etc google osx bluetooth 4 dongle site:dx.com, for instance Ultra-Mini Bluetooth CSR 4.0 USB Dongle Adapter - Black.