When moving to a new town with school aged children you have to make certain choices that aren't exactly in keeping with your personal priority list.
If Richardson is the town of employment - and your children's needs aren't met by the "local" school - you'll want choices. I have found this website INVALUABLE, because it gives directions and links to other townships in the general vicinity. It even gives you the number of miles away:
If you find your schools at http://www.greatschools.net
and are unimpressed by the stats - check out the other cities via city-data.com, this will give you additional choices and converesely the move to Richardson could be a go - regardless of the schools.
Disclaimer: I know nothing about Richardson schools - and I hope you find the one suited for you and your family. I just want you to know that if you don't find what you are looking for and don't mind a commute, you have other choices as well!
Good Luck in your Endeavors!