If you are prepared to stand over it stirring it then you can make it about 20-30 minutes using the traditional method - keep the heat a little higher and keep everything moving around to stop it burning on the bottom of the pan.

A few thoughts to help you make a creamy risotto...

Don't add tomato to it - the acidity in the tomato will stop the starches binding together, if you want tomato in it then leave it to the end of the cooking process.

It's really important to add the stock a bit at a time - the starch is released by all the grains of rice rubbing against one another as you stir it....if there is too much liquid at the start then this doesn't happen, so it doesn't get creamy. You can add the stock in larger quantities as the rice cooks as most of the starch will already be out at that point.

Making a risotto is not an exact science, so don't stick to times and quantities in the recipe too closely...if the rice isn't cooked when the recipe says it should be, then don't worry about it, just keep stirring and adding stock until it is ready - if you add too much stock and the rice is cooked, but the risotto is too wet for your liking then add a handful of grated parmesan and stir it through to pull it back together.

WRT to the stock - even if you won't make your own stock, then think about having a couple of cartons of ready made stock in the back of your cupboard - most supermarkets have a decent selection now, and they taste much better than powders or cubes. Suse's suggestion of adding a spash of white wine at the start is good, it helps develop the initial flavour base that your stock is lacking....also think about adding other veggies to the chopped onion at the start to improve the flavour - finely chopped celery and/or fennel will do wonderful things to the risotto's taste.