Agree with all of the above.
A 190 isn't really much bigger than an E30 BMW as has been said, I'm not sure that if you need more space that a 190 is the way forward.
There's two models that are referred to as 'Cosworths', both the 2.3-16 and 2.5-16. To most people they are essentially the same basic car, a fair few differences between the models but I guess that can come later. They are both 4-cylinder, 16 valve engines with double overhead cams. The earlier 2.3-16 models are 2.3 litres and this was increased to 2.5 litres for the 2.5-16.
Just to get something covered at such an early stage - these are definately 'enthusiasts' cars and are in fairly strong demand for decent examples. They cost upwards of £4-5k for an example worth owning IMHO, the majority of cars for much less than this will almost certainly be needing work in several places and I'd classify them as rolling restoration projects. Some of the specific 2.3/2.5 parts are rare and expensive to find so you need to consider such a purchase carefully. I'd personally look to spend at least this amount to secure a fairly good car as you'll end up spending more rectifying a lesser one in the long run. Good cars will hold their money very well providing you look after them properly and keep them original.
The regular 190E four and six cylinder cars (1.8/2.0/2.6) make much more sense for most people, they're much more affordable, cheaper to run and generally there's a wider choice of good vehicles as they were sold in much higher numbers. Even £500 can buy a reasonable car, £1000 buys a good clean 190E with no real issues, £1500-2000 gets you into the really nice/mint/low mileage cars if you look around, LEs/Sportlines/2.0s with all the toys/2.6s etc
Hope that helps you to start with
Will