@DarkStar811, to clarify, because you seem new to the game, they are taking your land with Liberty Bells. In Colonization, Liberty Bells have the same affect on city boundaries as Culture has in Civilization.
Produce them by assigning colonists or statesmen (don't try Converted Natives, Indentures, or Criminals — they're not as effective) to the town hall. But be careful. This means your people are preparing for independence. The king will notice and increase his Royal Expeditionary Force (REF), which is what you need to eventually fight. If you're not ready to declare independence, it might be a bad idea to produce too many bells.
Taking this into account, as well as the fact that the one of the English leaders gets a bonus for bells, M07 probably means the best way is to take it by force. It is possible with bells, but capturing is easier with fewer long-term downsides.