As such AS5300 is a end of life product ,you can use AS5350 instead which is a universal access server. Many modules are available with AS5350. For 30 analog users you may require a Next port digital modem which come minimum with 60 lines .
You can use it for future scalable network too, for PRI you can use Four-port CT1/CE1/PRI termination card. This is all you need and the licenses and the suitable software.check the detailed data sheet of AS5350. http://www.cisco.com/en/US/products/hw/univgate/ps501/products_data_sheet09186a0080091b55.html
Even you can try with the AS5400 too.
http://www.cisco.com/en/US/products/hw/univgate/ps505/products_data_sheet09186a0080091e51.html
