tomato diseases - need advice (have read msOlga's thread)

hi all,

I've just signed up and I did read about msOlga's problem with her tomatoes.

I have a similar problem only as I planted my tomatoes late (ie. I was slack this year) my tomatoes are still growing and I'm not sure what to do.

My tomato problem:
Yellowing leaves that I pick off (or if missed, turn brown and shrivel up) on my pots of tomatoes and now there seems to be a bit of powdery residue on the bottom of one plant (a good number of tomatoes have just set or are growing or are just waiting to turn red)

3 Questions:
1. Does anyone know what I can do about the above (ie. treatment or remove plants)?

2. Lots of the tomatoes are still green - is it ok to wait for them to ripen or should I pick them now.

3. Is it still ok to eat these tomatoes (they look fine, no blemishes and the small number that ripened earlier taste great)

I'd appreciate any help you can give me. Last year was my first try at growing tomatoes (and any veges for that matter) and they turned out great - big, plentiful and flavourful. This year has been difficult!