While it's very likely that a Dalek(s) figure is in the works over at Bif Bang Pow, if you can't wait (like me) there is a kind of an affordable fix available in the UK. In 1975, Palitoy released this talking Dalek toy (seen above) which blends in very well in the 8" set. It's a touch shorter than it probably should be but as you can see Brock has his hands full. If you don't care about a broken talk function you can usually get one for under $30, the one i have cost around $26.
The Palitoy Dalek was however, not made by Mego but by Japanese toy maker Tomy. Mego made one for Denys Fisher which is hard to find in any condition, it is a little more show accurate but will likely set you back $200 or more.