What can I still plant?

[spudtrooper]

Hi all, I took on an allotment mid december 2006 but after clearing some of it(still ongoing) I planted potatoes, potatoes, onions & more potatoes. Also a few strawberry plants, 4 outdoor tomato plants (never produced anything), 2 pumpkin plants that are running riot, but having lifted my first earlies what can I plant in their place that will be ready before the winter or something that can survive over winter. Soil is clay but not too heavy.

[spudtrooper]

[cornykev]

Check out Newbies posting lower down, "Really basic crop rotation question".