[Escobabe]

So, i want to make this when a player robs the casino, he can't rob it again until the time pass [30 mins]. I've done something like this.

Code:

CMD:robbank(playerid,params[])
{
	if(PlayerInfo[playerid][pVIP] == 1)
	{
        if(GetPlayerInterior(playerid) == 3)
        {
				new rand=75000 +(random(35000));
				new Pname[MAX_PLAYER_NAME];
				GetPlayerName(playerid, Pname, sizeof(Pname));
				new str[100];
				new str1[100];
				format(str,sizeof(str),"You've robbed the bank and got $ %d from the robbery", rand);
				format(str1,sizeof(str1)," %s has robbed the bank of Las Venturas and stole $ %d", Pname, rand);
				SendClientMessageToAll(COLOR_ORANGE,str1);
				SendClientMessage(playerid,COLOR_WHITE,str);
				GivePlayerMoney(playerid, rand);
				SetPlayerWantedLevel(playerid, GetPlayerWantedLevel(playerid) + 4);
				SetTimer("RobTimer",300000,0);
		}
		else SendClientMessage(playerid,COLOR_RED,"You're not inside the bank to rob it.");
	}
	else SendClientMessage(playerid,COLOR_RED,"You're not a VIP Member to rob the bank.");
	return 1;
}

And a timer, this is the part i dont know what to do.

Code:

forward RobTimer(playerid);
public RobTimer(playerid)
{
	SendClientMessage(playerid,COLOR_ORANGE,"You can now rob again.");
	return 1;
}

What should i add more? I don't know a thing about timers.