You don't state how far away from the router the laptop will be nor what it's wireless capability is.
Distance and the number of intervening walls/floors and wether or not they have metal reinforcement will all affect signal strength.Distances quoted by manufacturer's usually assume ideal conditions in free air which is rarely found in a home environment:radiated interference will also cut range.
If you plan on using the 'G' spec protocol (currently cheaper than the latest draft 'N' spec, and the laptop is reasonably close, a standard G spec modem/router will suffice. If you already have a modem with an ethernet connection than you only need a wireless router.
If you are doubtful about your local conditions it is worth investing in a model with MIMO capability (multiple input/output channels) which will significantly increase range.