Lua how to add time to this script?

[tompan]

function onUse(cid, item, frompos, item2, topos)
gatepos = {x=747, y=1043, z=7, stackpos=1}
getgate = getThingfromPos(gatepos)

if item.uid == 5006 and item.itemid == 1945 and getgate.itemid == 1353 then
doRemoveItem(getgate.uid,1)
doTransformItem(item.uid,item.itemid+1)
elseif item.uid == 5006 and item.itemid == 1946
and getgate.itemid == 0 then
doCreateItem(1353,1,gatepos)
doTransformItem(item.uid,item.itemid-1)
else
doPlayerSendCancel(cid,"Sorry, not possible.")
end
return 1
end

I want the stone to get back after 1 min..

 

[narko]

instead used addEvent