Arduino1.6.3 GSM Library - Arduino GSM Shield VS SIM900 GSM Module

Hi, I need a temperature sensor sending data to a server at intervals and a relay controllable through a gprs connection. I have the SIM900 GSM module. I used library from http://www.gsmlib.org/. The connection to web-server(GSM Client) works. But the program is slow and library takes up most of memory. (For web-server to Arduino I guess I need the GSM server code, I did not try, as this itself is not stable)

I tried using the GSM library that comes with arduino1.6.3 but it does not seem to work with SIM900.

q1) Can the GSM library included with arduino1.6.3 be used with SIM900 or is it only for the Telefonica Arduino GSM Shield? If yes what do I need to modify to make it work with SIM900.

q2)Is it really possible to have a bidirectional GPRS data connection with a Arduino Nano+SIM900 GSM Module with the www.gsmlib.org library?

Thanks bunch. -kk