How can I improve the security around my house and prevent theft?
Step 1: have nothing of value in the house worth stealing. This is easier to do than you might think. No reason to keep anything particularly valuable in a house that is being targeted for break-ins. Anything valuable you cannot bear to remove from the house should be hidden in a non-obvious location (think creatively). Now, if someone breaks into your house when you're not there, they don't get anything. No big deal. Eventually word will get around in the criminal underground and hooligans will stop breaking into your house.

Step 2: get a big scary dog and a handgun. Train the dog to bark at people approaching the house and bite on command, and carry the gun on your person while you are at home. Now, if someone breaks into your house while you're there your dog will bite them and/or you can shoot them (ignore whichever piece of advice offends you if you are not a dog person or a gun person). However kidnapping is an extremely serious matter and I urge you not to discount any potentially useful options.