GPRS antenna for bluetooth module
Two parameter of antenna which are important are 


Frequency range
Impedance


Frequency range of antenna which is shown with antenna's frequency present center frequency of antenna and it's bandwidth and Impedance which is used for preventing losses of traveling  wave travels through the device and antenna. Your Bluetooth modules run in 2 GHz band and GPRS is used in 900 MHz and sometimes 1800 MHz. GPRS antenna is modified for these frequency and it will has low gain in 2 GHz. Also it is hard to match impedance for 2 GHz. So, it is not suitable to use for Bluetooth. But i recommend see antenna specification and your Bluetooth band. If your antenna has gain in Bluetooth band with considering impedance it could be used.