Your grades at GCSE aren't great, but you did get As in the two most important sciences. Some medical schools ask for Bs in maths and English, which you don't have, but taking English to A level may help with that if you get a good grade (although on that note, is it wise taking an A level in a subject you got a C in instead of a subject like RS which you got an A in?).
The aforementioned 'So you want to be a doctor?' book really is great for strategically picking medical schools - I own it so I'll give you some advice from it! Birmingham, Cambridge, Bristol, QUB, Cardiff, Oxford, Hull York, Lancaster, Liverpool, Keele, Barts, Imperial, St George's, UCL, Manchester, Nottingham, Sheffield, Southampton, UEA, Edinburgh, Glasgow and Cardiff are all out for you because of your GCSE grades. All other medical schools - Brighton and Sussex, Newcastle/ Durham, Exeter, Leeds, Leicester, King's, Plymouth, Aberdeen, Dundee and St Andrews - may consider you if you do very well at AS level and have an amazing personal statement. (Please bear in mind that this information may have changed as the book was published in 2013 and some medical schools change their requirements). Also, many of those unis are 'out' because they need at least a B in GCSE English and Maths, so resitting those GCSEs to get at least Bs would open up some more options if you want them!