Italian stores in Houston??
The first 2 things that come to mind are Spec's Liquor Whse Deli downtown on Smith and Antone's in the Village on Dunstan. http://www.specsonline.com/ Click on 'browse the store' and you can search for specific items.
I believe the Antone's is the only 'original' one left and it's a small import food store in addition to being a deli.
Years ago I used to go to Andros on Fondren for mortadella, olive oil, etc. I haven't been there in years but I see it's still open (listed as a Greek deli on b4-u-eat.com).
Then I just found this on Google:
That's a new one on me but looks good.
Some of the big grocery stores besides CM carry a lot of imported foods.