Well if you don't want to re-mortgage your house then you'vr booked the wrong place!!!
£10 a pint, plenty of fish restaurants, and good looking local Icelandic women etc.
There is a restaurant in Reykjavik where you can go and get to cook the food how you like it at your own table!!! but very pricey.
Your best bet is to go to somewhere on the outskirts called The Pearl, it's basically 4 huge geothermal tanks with a visitor attraction built on top. They have an artifical geysir, but it also has a reveolving restaurant on the top floor with superb veiws over the city and glaciers in the distance. ALthough I couldn't afford to eat there I think an ice cream was £7
You'll have to got to the Blue Lagoon though and give that a try and if you get a chance take a trip to the Golden Circle (Gulfoss waterfall and the Geysirs), its also bizarre noticing the bananas growing in the green houses!!!!
But other than that you'll get the four seasons and come back fucking skint