I believe Peter may be correct in surmising that Loretta's Pizza Seasoning is a Canadian thing (it isn't, however, a WalMart thing, as I only found it there after originally finding it at a store called the Italian Market Grocery here in Edmonton).
In any case, I think the key discovery for me in achieving a true pizzeria taste to my sauce was the addition of salt, a little sugar, and olive oil to the tomato base and pizza seasonings. With just the base and seasonings, the sauce was nowhere near the same taste--quite inferior.
I couldn't even tell you exact measurements for those three additions (I have to measure it next time I make some sauce). All I know is, experiment with adding a good bit of salt, a little sugar, and a drizzle or two of olive oil, and I think you'll find your sauce much improved, no matter which pizza seasonings you try.