Another thing. In this picture:
http://img7.imageshack.us/my.php?image=namnlsgc1.jpg
Is this optimally a production city or a commerce city?
It's hard to tell, but it looks like those are Sheep on the farmed tile 1W of the city. You should research Animal Husbandry and build a Pasture on the tile. That will yield 4

1

I think--definitely more than the 3

you're getting from it now (though a Farm is better than nothing until you research AH).
Even with the Sheep, this city is going to languish until Biology makes all those Plains tiles worthwhile. Sure, you can work the riverside ones now by Farming them for 2

1

1

which is marginally better than working Grassland Forests, but the city will probably cost you more than it puts out for some time.
Turning the city into a production city, however, you can use the

from the Sheep and the city's tile to work both Grassland Hill Mines and both Plains Hill Mines for a total of 15

(counting the city's tile too). Had I settled here, that's what I would do with the city until Biology.
Once you have Biology, you're only real option would be to Farm four of the Plains to allow you to work Mines on the two Desert Hills, giving you an extra 10

(4 from the Plains tiles themselves, 6 from the Mines).
Turning the city into a commerce city, the best you can do is build Cottages on the 5 Plains tiles and one of the Grassland Hills (effectively a flatland Plains tile yield-wise). Early game, you won't be able to grow past 6 anyway, but as you raise your happy cap (your population limit due to happiness), the city won't be able to grow any larger due to its poor food options. Once Biology rolls in, the only way to take advantage of the better farms would be to plow under your grown Cottages--not a good option.
Given that, this sad little 'burb should be relegated to production for its lifetime.