since you are located in Mandaluyong, I would recommend Bengems Machine Shop. They specialize in printing machines and have been in the business for a long time. The shop is located in Old Zaniga near San Felipe Neri Church. Look for Mang Ben. Check the contact info at www.philprinting.com by clicking on the Suppliers Directory.
Another machine shop I can recommend is Dynamic Tools. Although not specialized in printing they do good work. The owner, Jess Celis, was a former instructor at Don Bosco. The shop is also located in Mandaluyong, at P. Cruz Street. Tel nos. are 5320502 and 5350183.