A. Around the clock is an expression that means "all (of) the time".
B. This should actually be "you're after the big bucks", because it is a contraction of "you are after the big bucks". One buck is slang for one dollar, and "the big bucks" refers to large amounts of money, usually in the context of a salary, or possibly payout from gambling. Being dedicated to money means that the person highly values obtaining money, and works hard only because of the monetary reward at the end.
When the person in the conversation says "I never thought you would be so dedicated to money", the situation being described is:
1) Two people have known each other for some time.
2) In the past the second person knew that the first was not dedicated to money at that time.
3) The second person is now surprised to hear that the first has become dedicated to money since then.
If the author had instead written "I never thought you were so dedicated to money" [note that it should be "were" instead of "are", because "I (never) thought" is past tense], the meaning would have been changed to describe this situation:
1) Two people have known each other for some time.
2) For that whole time, the first person has always been dedicated to money.
3) The second person was unaware of that fact until recently.