the price for the new battery doesnt seem high as RR's usually take a higher powered battery than most cars because of the amount of CCA required by the motor...
something to think about... if you at any point have had a dead battery and you get your car started and "run" the car to recharge the battery (considering your alternator is ok) it can take up to 3 hours or more (depending on the battery) to recharge it.
letting it idle for 20 minutes or even driving it around for an hour when you have the radio on wont be enough...
and no a year old battery doesnt not sound like a dead battery... are the symptoms you have now the same as when you replaced the battery a year ago?? if so maybe your alternator is going bad or something else is keeping the battery from recharging properly.
something to think about... if you at any point have had a dead battery and you get your car started and "run" the car to recharge the battery (considering your alternator is ok) it can take up to 3 hours or more (depending on the battery) to recharge it.
letting it idle for 20 minutes or even driving it around for an hour when you have the radio on wont be enough...
and no a year old battery doesnt not sound like a dead battery... are the symptoms you have now the same as when you replaced the battery a year ago?? if so maybe your alternator is going bad or something else is keeping the battery from recharging properly.