Thanks for the compliment, Jules001!
Don't even think about driving. Sign-posting within central London is difficult to follow unless you've got a map of London in your head. Driving is very aggressive. (I've been shunted in the rear by three different taxis within the space of 10 minutes!). You have to pay �8 per day congestion charge and parking is almost impossible to find. (If you can find a parking space, it's likely to cost you between �4 and �10 per hour).
National Express coaches arrive at Victoria Coach station, which is a 5 minute walk from Victoria underground station. You've not said precisely where your hotel is located, so I can't give you exact directions but the London underground system is easy to use, so you'll have no problems in finding your destination. (If your hotel, like the Palladium, is served by Oxford Circus station, it couldn't be easier. First, walk to Victoria underground station. If your absolutely certain that you're only going to travel to Oxford Circus, purchase single tickets at �4 each. Otherwise purchase off-peak Day Travelcards for �5.30 each. Follow the signs for the Victoria Line and ensure that you're on the northbound platform. Trains run every few minutes. Oxford Circus is just 2 stops along the line, with a journey time of just a few minutes).
If you could find a way to get to Birmingham cheaply, Megabus are offering seats on 14/02 from Birmingham to London for between �1 and �12.50 (depending upon the time of travel), with fares for the return leg of between �5 and �14.50. However, National Express from Birmingham would obviously be simpler.
Chris