Polyanthus often produce some flowers in autumn though not as many as their spring flush. Similarly Viola's including winter pansies do the same with a few flowers during winter but make sure they specify "winter flowering".

Some small shrubs such as Sarcococca flower from late winter into early spring. Indeed most "winter flowering" plants tend to do this though many are shrubs and trees.

Heathers make attractive container plants in the short term and can be planted out in the garden later. Some have attractive foliage especially the coloured variants of Calluna which can also be added along with Ivy and the above Pansies or Polyanthus. Ajuga especially the coloured leaved forms can look good too.

All can be grown in multi purpose compost (including the heathers) so will suit all.

There was a question a couple of days ago about plants for containers in winter -
http://www.growsonyou.com/question/show/29637
The answers may be useful to you.

I love Ornamental Cabbage plants and they last for ages