Hi James,
You've raised a few different issues.
First of all, while the kit lens is a great lens, it is, as you've already identifed, optically slow.
Let's start by addressing that issue: for under $200, you can get yourself a 50mm f/1.8 lens. Sharp, fast, inexpensive, and about as good value as you're going to find anywhere, any time.
As a starting point, through this site it's just $Au167 delivered to your door. You may find it cheaper elsewhere, but my point is that this is a very inexpensive and flexible way to start to overcome some of the issues that you're seeing.
bimborocks wrote:sometime i find that i don't have enough light with the inbuilt as well as on close ups the flash seems to be really concentrated/direct.
This is mostly an issue of ligh balance: what you need to do is to learn about Flash Exposure Compensation (FEC). This lets you dial down the flash unit's output, and permits you to get a better balanced exposure.
Make sure that the camera is turned on.
Using the on-camera flash unit, pop the flash. Now, (and we're looking at the camera from a "photo taking" position, behind it) hold down the flash release button. That's the one on the left side of the pentamirror housing, above the lens mount. While holding this button down, turn the front sub-command dial, and pay attention to the LCD display. As you turn the dial, you'll see values like 0.3, 0.7, 1.0, or -0.3, -.07, -1.0 etc cycle through the display. This is how much (or little) extra power you are giving to your flash.
Start with a setting of -0.7 (under expose 2/3 stop) and see where that takes you. Play with different settings and different subjects, and learn and understand what works for you in what circumstances.
have seen some stuff on using external flashes to bounce light and use difusers to get a better and more even coverage of light.
Yes; these are basically all good for off-camera flash, but the built-in unit is surprisingly good once you understand some of its capabilities, and yes, you can diffuse that too. Try taping a plain white kleenex to it, for instance, taking care to not cause it to interfere with your lens.
i would also like the flexability to fire the flash from the side or angle to get differant effects - particularly when shooting fish and corals in my fishtank
Reflectors are good for this as well, and there are small, cheap flash units that can be used as slaves as well.
For now, I'd try to master what you have, but also consider the 50 f/1.8.
And for shooting into your fishtank, if you're using flash, never shoot directly at it, 'cos all you'll get will be a reflection from the glass.