Replacing rear hub, beginners advice required I have a Trek 1.5 2011 compact road bike that I abused a bit too much over winter.

The rear hub has quite a lot of sideways play on it and I am buying the tools needed to hopefully fix this. My concern is that even if I manage to remove the play on the hub the bearings will still be ruined (fairly likely).

What I'd like to avoid is having to remove any spokes.. the idea of building a new wheel scares me quite a bit! Or perhaps I'm being afraid for no reason?

What I'd like to know is what my options are if I find the bearings have had it. I don't really know what I'm talking about but in an ideal world I'd just replace the hub with a drop in replacement. Does that exist? :) I don't mind getting my hands dirty, but at the same time I want to ensure I have a bike to ride!
There's two general types of wheel bearings: cup and cone and sealed cartridge bearings. 

Cup and code bearings were very common years ago and are even still used on some high end Shimano hubs (dura-ace). http://sheldonbrown.com/cone-adjustment.html. These bearings are easily replaceable with minimal tools. If you have these bearings and have worn them down too much, they can damage the bearing race in the hub. In that case you'd need to replace your hub.

Cartridge bearings are more common today. (http://www.pinkbike.com/news/To-the-Point-Cartridge-Bearings-2013.html). The advantage of a cartridge bearing is that even if it wears badly, it's not going to damage the hub. The disadvantage is that they are pressed into the hub shell and require more (and expensive) tools to service.

I'd be surprised if your bike had cup and cone bearings, but the only way to know is to do a little investigation. If the races aren't worn, replacement is quite easy. If you have cartridge bearings, any bike shop can easily press out the old ones and press in the new ones.