Warhammer Historical and Games Workshop do not currently produce any Historical Miniatures, although it's fair to say some of our catalogue could easily be used as substitute figures in order for you to start playing. You can also find some suitable back catalogue figures, especially from the older Bretonnian ranges available from GW Mail Order.
There is a wide range of Historical metal miniature manufacturers, with a range of scales and prices to suit all budgets. The back pages of the Warhammer Historical books usually carry a detailed resource section, including contact information for a number of these manufacturers and this is a good place to start.
Many hobby and toy stores also carry an extensive range of quality soft plastic miniatures. These offer an excellent low cost way to start Historical wargaming and was the way many of us here at Games Workshop first started wargaming when we were young. Your local independent Games Workshop retailer probably has information on these and they should be able to assist you. If they cannot, ask them to contact Warhammer Historical.
Alternatively, our retail staff in our own stores should also be able to recommend some local hobby and toy stores, and certainly should be able to assist with models from our own ranges, so pop in and see them today. There are also a number of Wargames magazines with advertisements of suppliers. or just search the web.
A good starting point for miniatures suitable to use with the Warhammer Ancient Battles rule set and supplements is the
Society of Ancients web site.
Hope that helps and enjoy the games!

Carthaginians ready for battle.