Hi Sam,
There are a few things you can do to repair hair damaged by overuse of heat tools. If you're going to continue using the heat tools, then you need to use a good preparation product to provide some heat-protection whilst styling. These are easy to find and most good salons will do a range suitable for your hair type and be able to advise you how to use them. When styling with heat, they give off a mist or 'steam' and this is the product burning off and protecting your hair from the drying effects. Obviously, the ideal scenario though is to avoid heat styling as much as possible, especially if you know you've damaged your hair already.
In that instance and in terms of styling, try a salt-spray for those beachy, wind-swept waves. Bumble&bumble developed the original 'Surf spray' (now copied by numerous cosmetic companies) to create definition, texture and volume in natural wavy hair and it can be cocktailed with other products to add more polish if you want a more elegant, evening style. You can either spray it through the roots and lengths and leave to dry naturally or style it with a dryer if you prefer. They also do a range called 'Straight' which helps you achieve the straightened blow-dry without the straighteners and is much kinder to your hair and would allow you to keep the style without so much damage.
There are also products you can use to repair the damage to your hair caused by the straighteners and dryers. Bb also make a product range called 'Quenching' which is profoundly hydrating and was developed for exactly that purpose; restoring natural moisture, softness and strength. The complete range includes shampoo, conditioner, leave-in styling complex and deep conditioning masque, but you can mix and match depending on what you think you need most. They're like antibiotics for your hair and as such should only be used for a limited amount of time to regain the moisture lost through heat-damage. Once you're happy with the condition again, return to an everyday cleansing and conditioning product and just treat your hair with a Quenching masque every so often to maintain it. You can return to the products whenever you feel like the condition is suffering again.
Hope this helps!