You have armed all your men with muskets, but your miltia may be too small to stop the professional Spanish conquistadors that are advancing upon your colony. The first skirmishes have gone poorly for your side. Within a month, the Spanish will be attacking your colony. You prepare your best defense to stop them.
However, there may be help nearby, in the Caribbean sea. For years, England has been providing letters of marque (contracts of war) to the pirates of the Caribbean to attack Spanish ships in the name of England. Perhaps you can send a ship to seek their aid. However, be forewarned that pirates are the worst sort of scoundrels and criminals; and if they choose to help, there will be a price to pay. Will you be able to afford what they demand? Or perhaps they'll rob you, take everything you have, and simply sail away. These privateers may be a greater danger than the Spanish.