Replacement window balance

We purchased our house just over 4 years ago. The previous owner was meticulous with the history of repairs and replacements, except when she replaced the windows. Several of our windows have broken balancers that we are trying to replace (I know how easy it 'can' be) but we can't find the correct balance. Currently we are unable to get the out of the window but we know its double hung, quick tilt, tape balance. We also need the pivot bars which have been impossible to find as well. Hopefully you can help or point me i. The right direction! Many advanced thanks!