It all depends on how far you wish to go and, eventually, what type of car you have in mind.
For fast road use, my opinion is to go with 33 16V items. That is, Sachs/Boge front and rear shocks and springs. The springs are a bit shorter from those you have and the overall visual effects shall be better too. You can get item codes at Sachs website: www.sbcats.co.uk
As for the front anti-roll bar, that is what I did for the Sprint and I'm quite happy. Alternatively, you can fit the Eibach anti-roll bar set (front+rear) but I think this is too much for a 1.5lt (you shall never produce that much cornering speed as a 1.7 16V). And they are not cheap...
Bushes are, IMHO, the first think you have to look into. New stock items shall totally transform the car. You can also start experimenting with urethane bushes, but I suggest you do it in stages and see how the car handles.
Finally don't forget to install the front top-mounts of the 33 Nuova. Possibly your steering troubles stem from worn top mounts.
All this is a good starting point, you can easily end-up spending thousands if you go balls to the wall with every concievable high tech solution. Before you start fitting coilovers and adjustable shocks, decide what you want to end with.
Oh, and I suppose you have already fitted good tyres and alligned the wheels correctly, haven't you?
Hope this helps