I lost all my remote for Mitsubishi Adventure Super Sport year 2000 model.

Do I have to buy a new alarm system to replace this? Or can I just buy the remote? Which is the cheaper option? Will I also have to replace the central-locking system if I get a new remote/alarm system?

Do you know where I can get the remote? Do you know what brand is the alarm system of Mitsu Adventure (cobra, etc.)?

Thanks for your help in advance.