You don't need to add a crystal or resonator to reset the fuses, as long as you have an external clock source. Some ISP sketches similar to Arduino as ISP can provide an output PWM clock source to feed to the target m328P mcu that is expecting a crystal or resonator.
See Gammon's notes about "alternate clock sources" at, http://www.gammon.com.au/forum/?id=11637
And then the "Programming the Bootloader" section right below that. His programmer sketch will output an 8MHz clock source on the programmer D9 pin that you can connect to the target m328P XTAL1 pin. Use the Lilypad 8MHz selection. This should get you started to change the fuses to internal. From there you can then reprogram it via standard IDE burn bootloader process.