These 2 lenses are more than enough... but what you really need is good lighting.
There are some continuous lighting equipment on sale in the mass sale section, or you can go to Ikea and buy the cheap lamp holder, and then go to a supermarket to get the most powerful white light bulb. This is what I started with. Another way is to get multiple flash/strobes.
Lighting makes the world of difference when taking photos.
Like zac08 said... lighting is a whole area on its own... and for me, there is so much to learn about lighting. When I started out, what I did mainly was trial and error... so some shots turned out ok, some didn't... but don't give up
I currently use a pair of matching strobes, one on each side about 10 o'clock and 2 o'clock from my cam position with a much lower powered strobe behind from top to light up background. 50mm in a small light tent should be enough but stop down as much as you can if you are going for overall sharpness. I also find that elevating your product with a sheet of glass on some form of stands also works really well. No shadows on glass.