3 hours a day is plenty for this goal. This big obstacle will be the 450/wk tomestone cap, so you will want to optimize your play and start hitting that cap ASAP. Once you're geared enough, one expert roulette per day is enough to hit the cap before the week ends.

Now if you want to raid and get dreadwyrm gear, this is generally a more serious time commitment and 3 hours per day may be difficult.