Actually the best solution for the mouse and keyboard with playbook, is one of two solutions/suggestions:
1. You can of course buy from, shopblackberry.com a keyboard for the tablet;
Or:
2. The solution I currently employ, use your blackberry smartphone through the bridge application. Of course, for this method to work, you will need a blackberry device running OS 5 or later to be able to download the app, from app world, to your device (free produced by RIM). Sidenote, this comes pre-installed on the tablet. And the bridging is simple bluetooth pairing, or using your device to scan a barcode created by the tablet. Once this is completed, simply access the app (bridge) on the smartphone, and set the option to enabled for the device to act as a keyboard and mouse interface.
*. Extra sidenote: after you are done using your device as the keyboard/mouse input, and wish to return to tactile interface with the tablet; always, press the menu key (7-dot button), and choose disconnect, this will keep the bridge connected, but return input control back to the tablet.