is it possible to get new alarm fob,without changing the alarm?

hello,ive lost my key fob and was wondering if it is possible to to get new key fob without changing my alarm?the place it was purchased has closed down,this is the information i can see on the siren.auto siren,6-12 vdc 100ma,ves-35hp vimpex ltd.and there are two sirens.i would appreciate any infomation you can give,thankyou chris.