Haven't done a Cooper's lager kit, but I'd imagine that its not meant to be a very heavy beer to begin with, and since the honey should ferment all the way out, it could lead to a drier beer. That being said, 1.003 is still pretty low. Did you take an initial gravity measurement? How much malt extract was in the kit, and was there any other plain sugar or was it just the honey?
Assuming your hydrometer measurements are accurate, there's not a lot you can do at this point to bring the final gravity up. I've heard of people attempting to do so by steeping some crystal malt in some water, boiling quick to sterilize and adding the fermenter to provide some unfermentable sugars, but I've never heard how they came out.
More than likely, you've got two options now.
1. Let it sit on the yeast for another week or two, wait to make sure the gravity isn't dropping any more, then go ahead and bottle as normal. It might taste dry now, but a little co2 will increase the mouthfeel and might turn into a tasty beer.
2. A little more complicated, but there are certainly things you can add to beer if you are feeling up to it. One would be to dry hop with an ounce or so of hops. Probably way out of style for a lager, but who doesn't like hops?
You could also backsweeten with a little bit of lactose or add some fruit (whole or extract) if you wanted to go that direction.