Different Manufactures use different hubs, also the offset is different so a wheel designed for a vauxhall for example isnt going to fit your Clio. If you dont get the hub spacing / offset right your wheels will rub your bodywork or foul your steering arms / suspension. Also you might need to get your tracking checked again, also you might need to get your camber checked so that all of the wheel is flat on the ground. Otherwise its just going to handle even worse than it does now and also you'll get uneven tyre wear.
If your going to do it go to your local Halfrauds, waste the time of the morons in the Ripspeed bling alloy tat department, get them to tell you what size wheels are going to fit your car. Say that you are going to think about it, then go back home and go through ebay.
Remember even cheap tyres in a larger size are still going to be sh*t. If you want your car to handle properly. get Renault wheels designed for your Clio and spend some money and put decent tyres on it.
Personally I still think its a waste of time putting bigger wheels on your car. I still think it'll handle better if you stick to standard size wheels and speed some money on good tyres. Rememeber the suspension etc on your Clio was designed to work with the wheel sizes it has on there now.
Why not see if theres a Renault Clio owners forum or website, bound to be more info on there about what will or won't work.
My fiesta handles sh*t, its utterly cack compared to my Golf GTI, which again was sh*t compared to the Porsche 911 that I've driven. You've got a Clio its never going to handle like a sportscar. If you want better handling buy a better car.
Edit, theres loads of Clio wheels on ebay..
Ebay Linky