Elli - I know what you mean about freezing fingers. When it is really cold it doesn't matter how many pairs of gloves I wear my fingers still freeze. The only thing that keeps them warm is to wiggle them! So long as I keep them moving they stay warm - strange I know but try it, it does work.
I don't know what to do about toes though, I think wiggling your toes while running could cause problems.
To see the general standard and where you are at you should have a look on the www.ukresults.net website and have a look at the results of some 5K races. For example in the Hyde Park 5K in Leeds a time of 25mins would place you 60th out of 80, Lancaster 5K - 88th out of 100 etc. However, improving to 21 mins would place you 34th and 54th respectively.
p.s Becareful with athletics clubs if it is running that your daughter enjoys. At that age a lot of athletics clubs try to get them doing a little bit of everything. If you daughter likes sprinting, jumping, throwing and is reasonably good at them then she will have a great time but I know when I was that age, I could run and run all day but was hopeless at any other type of athletics and would have been completely put off. All I wanted to do was endurance running and there is very little focus on this for youngsters at a lot of athletics clubs. Some clubs with a strong cross country section may be better on this as there are cross country races for primary school age.