Renwick says it is the first time in 21 years that the centre has been broken into.
"We never had a problem, we were able to leave the doors open when we were going down the road. We always operated on trust, so it is really disappointing," she says.
"Replacing equipment is quite hard, I think it will take two to three months to get everything back to where it was. But we had donations given to us already, so I am hopeful. This shows there are people out there who care."
The celebrations on Saturday will still go ahead as the local theatre has lent the centre a sound desk.
The festivities on Saturday include a family open day with live entertainment, games, prizes and screenings of short movies the centre created over the years. In the evening, there will be a musical show.
The Future Te Aroha Centre has been providing a range of community services, including after-school activities, community groups and school holiday programmes.
It operates as a community and cultural centre in the former Bendon factory building in Boundary Rd.
Renwick, who has been with the centre since it started in 2001, says she will "gradually step back" from her role with the centre.
"I am going to retire, but I will still stay in touch with the centre and teach acting classes. I leave things in the capable hands of Dianne Toogood who is doing an excellent job."
Renwick's involvement with the centre was sparked by the closing of the Bendon factory which had around 130 employees.
"I wanted to turn a negative into a positive and gather people who believed in the future of Te Aroha. It is all about the community."