I saw some report somewhere that showed by subject how USMLE takers from different countries compared to US students. I tried to find it but I've either deleted it or lost it. Sorry!
Anyway, the good news is that students from Ireland did just fine in pathology, physiology, and pharmacology. The two subjects we got killed in were Biochemistry and Behavioural Science.
I can personally say that in my practice tests I was doing REALLY badly in those two subjects and molecular biology as well.
I'm not sure how UCD compares to UCC but for our micro we didn't get a lot of emphasis on lab tests. I was doing great on "clinical" micro questions but not so hot on the laboratory type questions. I think I bought BRS microbiology (in addition to Micro made ridiculously simple) and BRS molecular biology. Both have no pictures - just straight text - but they helped me a lot.
Also remember, just because Behavioural Science is fluff doesn't mean it's easy. Well, it isn't hard or anything but I think it took me a lot of practice. I found the worst thing about BH was that often all 5 of the possible answers on the real test sounded WRONG where as a lot of the commercially prepared USMLE questions for BH had 5 answers of different shades of RIGHT. There often wasn't a great option on the real test and sometimes all of the answers sounded at least mildly inappropriate and I had to pick the least worst one. I found some of the better question banks really did a better job of preparing me for the BH questions then some of the review books did.
Best of luck studying. It's a beast!