Unfortunately thats a lefthand drive and the brake fluid is on the right Leo, the power steering resorvoir is near the oil filler on that picture, it has a symbol of a steering wheel on it and will be ATF fluid (automatic transmission fluid) contained therein on this car, some cars use different fluids and using the wrong one can result in a very expensive mistake.

Really if you are not sure pop the car into a local independent garage and ask them to point out the basic top up areas and which fluid to use.

When you check the engine oil as already explained you must make sure the car is on reasonably level ground, most cars are roughly a litre between the minimum and the maximum levels, Vauxhall use 10/40 semi synthetic.

If you are not well into DIY car mechanics then stick to the basic things, oil, coolant, tyres, lights, screenwash < not washing up liquid as it goes all gloopy.

Battery leave alone, brake fluid, test the warning light works by pressing the button, do not top up unless its below the minimum. Same applies to power steering, it should not loose fluid, if it does it requires attention.

I must stress that "tinkering around" with a car is not recommended unless you know your stuff. It is never a substitute for proper servicing schedules and to ignore important changes/ schedule points, could result in expense, breakdown, and even serious accidents.

Things like Engine coolant and Brake/clutch hydaulic fluid (Brake fluid) require changing at regular intervals to preserve the life and safety of components.

Antifreeze (engine coolant), does not loose its antifreeze properties unless excessively diluted, but the anti corrosion property does degrade, so a complete change is recommended every 2 to 3 years.

Brake fluid is hydroscopic, it absorbs moisture from the air and requires changing every 2 years. It important!!

Thanks everyone, I seem to be even more confused now, I went to buy some anti-freeze, and it said something about draining the radiator first, well that is well over head, I thought it would just be a case of topping up in the plastic bottle thing, there's no way I would even consider doing something like that, I think I'll either have to get the garage to do that or not bother and just hope it's alright.

Just top it up, it'll be fine. The garage can drain it if necessary when you go for your mot and some places give you a free winter check on your car eg ATS. If you did all these things people have suggested you will never be done!

You don't need to drain the cooling system, just top up with AF.
Anti-freeze has a life span of 5 years before it needs changed.
PS: Don't get confused with the brake, power steering reservoirs, if you put the wrong fluid in either, it'll cost you a fortune, or your life.