I agree with the comments regarding DAB. It's great for a small radio in your bedroom, but the signal bandwith from most staions is just not good enough as a main source for hifi (FM can often be better depending on the station, although of course you may use your current player for that anyway - and if that is the case ignore what follows) so if radio is your main thing then it could these days be far better to look at a cheap streaming/media player option to allow you to access internet radio (and media streamers some have DAB too). In fact, there is currently a very tempting Denon DNP-720AE ex-display at Sevenoaks for £179 which could be a good swap for your current source assuming you have broadband access (although as ever spend more and get more).
In terms of speakers (and these will definately make the biggest difference), I've been happy with my Mordaunt-Short Aviano 8's which are currently £500 new (Richer Sounds), down from £750 when they got the 4 star review here. They should be big enough to fill a large room too. However, as has been said s/h could be your best option - the beauty of looking for floor standers on the likes of ebay is that they are normally buyer collect rather than post due to size, and that will cut down the bidders considerably to those in the local area (often not many). The result is that in my experience it is the componant where you can regularly pick up some serious bargains, although of course you can loose as a seller for youre existing boxes unless you are prepared to offer courier yourself.