there's a good reason you have only found ranges for your ideal weight and that's because:
1) Our body weight fluctuates regularly,
2) Our body weight is affected by our body composition (ratio of fat and muscle for example) and
3) At the end of the day there is a healthy range for your ideal body weight within which there is a point at which "you" feel most comfortable and happy (it's an individual thing).
There are a number of ways that you can determine your ideal weight range, but these themselves only provide a guide.
For example, our Body Mass Index
is one guide, but this isn't really applicable for heavily muscled people or pregnant women for example because it doesn't make allowances for larger than average muscles and carrying babies.
Usually the best approach is to not just use "weight" as your guide but also use body measurements (hip to waist ratio
for example) and percentage of body fat measurements.
I hope I haven't made you more confused than clear on this issue, but as you can see there is no exact ideal weight other than that at which you minimize the known health risks associated with being overweight or underweight and feel good and comfortable about yourself.
Good luck with finding "your" ideal weight and please let us all know how you go with it!