i guess you have power nothing?
Do you want power windows too?
Because if it were me, I would go all the way and do a factory grade retrofit of power everything all at once. (power mirrors is separate tho.)
Interior front door panels will have to change, you also need a different integration relay - a blue box clipped to the back of the dashboard fuse panel. You need one that is beige and has an extra connector.
EDIT: It seems you want to be able to lock and unlock your car remotely as well. An alarm system will do that, but most requires you have power door locks first. If you don't even have PDL, the above apply. Otherwise go shop for an alarm - the usual caveat emptors apply.