You should try the demo of Mount and Blade: Warband before buying it, because although the graphics may not be as shiny as modern games, that doesn't mean it's suitable for low spec gaming.
It can be quite processor and memory intensive, especially if you get into a battle with 100+ individual units on each side, each with their own horse and various projectile weapons each with it's own flight path.
Your laptop may be able to run it, if you turn all the settings down to their minimum and disable all of the physics and reduce the battle size, but it may not be as much fun when it's hobbled like that... for instance you'll still get into battles with 500-1000 troops on each side, but due to your restrictions you may only be able to have 50 on the field at one, so an epic battle will turn into a repetitive skirmish on an empty battlefield with waves and waves of reinforcements (and bodies that have to disappear as soon as you kill them).