Your plan of 'transferring' your JAR66 into an FAA A&P licence I'm afraid is not possible. The system in the USA will give you no credit for the JAR66 licence, you will have to start again.
On the bright side, the theory knowledge gained during the 66 process will hold you in good stead, but the exam will still have to be passed. You also have to prove you have enough experience to even sit the exam, your 66 will at least give you that, as I understand the system.
Getting an FAA A&P licence is not impossible as they have school's specifically set up in the US for the purpose. Two weeks exam training in one of these schools is about average for an experienced technician. After the 'training' you will go to an exam centre and try to pass 5 multi choice exams. Its done in front of a computer screen and the results are given to you immediately.
Once you pass all 5 you are eligible for the second part of the exam process. All the questions are published, and the school will test you on most of them during your 2 weeks your there.
Part 2
You will have a practical and oral examination with a representative of the FAA. If your only 'experience' on aircraft is through college and the bit you need for the 66, then you may find that element of the exam difficult.
Hope the above helps. If you need more info send me a private message and I will give you my work number.
Regards
The Doc