
Pregnancy in a queen you tell by the teats. 3 weeks after mating they turn pink, 4 weeks after mating they double in size -but the size isn't as obvious if she has had 2 or more litters before. But other than that, you cannot tell when she is due, there is no way.
Most cat pregnancies are 65 days. 63 is also normal, and anything up to 7o is perfectly normal. Queens cannot give birth earlier unlike bitches, the kittens just won't make it. So 9-10 weeks.
Kittens start moving about up on their legs at 3 weeks, but won'l walk PROPERLY until at least 4 weeks, should start solid food at around 6 weeks, and should stay with their mum for THIRTEEN WEEKS. The very sad thing is that most moggy kittens are taken away much much too early, before they are anywhere near properly weaned. They do need to suckle for a the very least 10 weeks but preferably longer. I've had kittens not even taking solids until 10 weeks -although moggies tend to be more advanced than pedigrees. You don't really want to encourage solid food already at 3 to 4 weeks as some people do as their organs just aren't mature enough to cope with it. 6 weeks is a good age to introduce solids at first.
The very best and safest thing would be to try to catch her and confine her to a cage or small room. Is there a local rescue that perhaps could help you out?