[DeitY]

Try like this, i'm not that much experienced..

//YCMD/ZCMD command buyweapon
if(!IsPlayerInRangeOfPoint(playerid, 2.0, 314.2579,-133.7782,999.6016)) return SendClientMessage(playerid, 0x21DD00FF, "You are not in right place. ");

ShowWeaponDialog(playerid);

anyway why are you sending 3 sendclientmessages for nothing, even if hes in that range he'd get 3 messages..

// your code