Thank you for the information.
As far as I can see, the MP C2500 does not appear to be a printer supporting the driverless AirPrint technology, so some kind of printer driver will be needed.
PostScript is mentioned in the MP C2500 specifications (optional?). You may want to check whether your printer can use PostScript.
The download, was that the aforementioned 3.7.0.0 driver (PPD installer)? Any special instructions about PPD installation with the download?
Would it be correct to assume that a Wi-Fi router is used? You said that the printer is connected through Wi-Fi. Does this mean that the connection from the printer to the Wi-Fi router is wireless, or does it mean that the printer is wired (Ethernet) to one of the LAN ports of this router? In both cases, you should be able to print wirelessly from the computer. Is the connection to the printer OK?
Regarding how to add a printer, see the Add a printer on Mac article above (if necessary, see the Add a network printer by its IP address section for details). Do you see anything related to your printer, or any generic drivers, in the Use: field in the Add window?