How to improve already bottled beer

My first home brew was made from a Muntons Midland Mild Ale kit and a "beer Enhancer" from my local HBS. The beer enhancer was a 1kg bag of various sugars and hops to compliment that particular type of beer.
It's been in bottles for about 2 months now and it has overwhelming malt flavours and not much else. It's also too watery.
Do you have any suggestions on how I could make it better? Could I pour the bottles back in to a carboy, let it go flat then add some dextrose, hops and yeast?

Personally I think I'd just do another batch instead of putting in all that effort to improve an already bottled batch. With all the work involved you could do two more batches. Also all that pouring will lead to a lot of oxidation, so there will be an even greater chance of your beer having other off flavors or even becoming infected.
Generally I'd say 2 months should be enough to see what your beer is going to be like, but maybe another month in the bottle will help. If not, use it to cook with while you get your next batch going.

Yes, what Wolf said. I had a batch I didn't care for- so I just ignored it for about 3-4 months. I needed the bottles, so I was going to dump it. I opened one and it smelled pretty good- tasted it and it was fine. Not great, but fine. My best friend loved it! (Go figure). She and her boyfriend finished a case and a half.

Time can't hurt and might help. There probably isn't anyway to improve it without risking infection and/or oxidation. The other thing is- you made a mild kit. I think the hallmarks of a mild are malty flavor with little to no noticeable hops aroma. Adding sugar or something now would just thin and dry it out even more. So, chalk this up to experience and brew something totally different.

Find another beer you don't care for and mix, or "blend" them into something more drinkable.

Thanks for the advice.
I'll put the bottles down in the basement and let them gather dust for 6 months or so, then I'll hopefully be nicely surprised when drinking the next one.