[cecile]

I agree with both Barry and Dave.
I shoot 31 lbs and I reach easily 70 m (I tried 90 m for the fun of it, but I need to aim above the target...).
As for increasing bow weight and if you have enough stamina, do it very gradually (add 1 pound at a time if you can). It will prevent bad surprises like injuries or too much decreasing in your results (during the time you shall adapt to the new weight) that may lead to demotivation or mistakes in your form.