去美國升大學ge 考試

usually university are not required for SAT. and toefl are really depends on the university you are willing to go..

SAT will test your science, math and english.. you can apply the SAT online
i am not so sure about the ACT.. but i remenber it's about act.. [i mean language act here..]..

for the "45 quarter hours, or 30 semester hours", is the credit you earn in high school or college. if you were study in high school HK. I am sorry you said you needed to take the SAT or ACT coz HK's education system didn't earn credit for transferring to university. basically, the credit thing is something that you dun have.

SAT 同 ACT 係美國大學入學基本要求 除非你入社區大學
你可以上SAT個網到check..香港應該有得考
http://www.collegeboard.com/student/testing/sat/about.html
SAT 考英文,數學加作文
ACT 要考埋 science so prefer SAT