It all depends on how much the lost files are worth. If it's really important, then go to a data recovery company. It won't be cheap...but then divorce isn't cheap either! Do a search on Google for 'data recovery' - there are a number of companies in the UK. Shop around. It's really not worth messing around trying free utilities etc. if the files are important. I'll just reiterate what Mac said: don't use your PC if you plan to go down this route - you'll only increase the likelihood of overwriting the lost files.
CD-Writers are dead cheap these days. It might be worth investing in one to back up important stuff once in a while.