Found this page with some tips and recipes on it that may be of use, the article recommends four thieves vinegar (the stuff they used in the days of the plague to help provent getting infected), there's also a salve to help prevent pests biting www.altnature.com/library/repelling_insects.htm
On the subject of Four Thieves Vinegar there is another website giving a different recipe than the site above www.advance-health.com/fourthievesvinegar.html love the suggestion to turn it into a salad dressing with the addition of warmed organic coconut oil.
I have read that a tea from an infusion of black walnut leaves (Juglans nigra) can act as a natural insecticide. Calamine lotion will help soothe the skin of anyone bitten by bed bugs, neem oil is also reputed to work. The apparently don't like garlic and won't bite people who have eaten garlic. I've also just read a claim that pure vanilla extract will act as a bug repellant, not a property I'd ever associated with vanilla before, anybody know anything about this?
You could also try one of those electronic pest repellant devices, they use no chemicals and are safe for humans and pets. Something else you can do to help get rid of the bugs, if it is indeed bed bugs you're being plaqued by, is when the temperature is colder than 25 degrees F, place mattresses and furniture outside for several hours to kill the bugs, although this may not be practical in a flat unless you have a veranda? Wash all your bedding, curtains and clothing on a boil wash until the infestation has gone. Sarah is right though you're local environmental health people would be worth contacting. Hope some of the above proves useful?