You will lose quality whoever does it. Boots do enlargements and so will any other company/shop that develop photos.
Can't give an indication of price without knowing how big you want the pics, how many you have etc. Try looking at the websites for Boots etc, they should have prices on there.
The best result will come from chemical prints directly from the negatives. If you no longer have those, scanning with an hi-tech scanner such as a professional photographic shop would use is the next best option.
You get what you pay for. See your local yellow pages for pro photo shops in your (nearest) town. Forget the online ones if you want quality.
The photos were done by a professional photographer but he no longer owns the business and i have no contact details for him, so anyone know how i will go about it now??
if the business was sold I would think he sold the copyright to the new owner - contact them. If not I wouldnt know what to suggest but doubt you will find anyone on the high street who will touch them. Hope you find a solution to your problem x