The facility has already helped groom 100 national and one world champion as well as Commonwealth Games medallists.
Ms Jones, 18, from Bangor, Gwynedd, recently brought back a gold medal from the Youth Commonwealth Games in Apia, Samoa.
The grant-funded extension has new physiotherapy and activity areas.
Gold medal weightlifter Catrin Jones has opened a £125,000 extension at the Holyhead and Anglesey weightlifting and fitness centre.