Welcome aboard!
I can certainly relate to your experience of the doctor sending you on your way with antibiotics for months on end. My doctor used to tell me the same thing over and over again and that it would work eventually. Credit where it's due, he was partly right, but for me there were other factors and triggers for my acne such as diet - things the doctor never mentioned or suggested I look into.
With antibiotics, you should start seeing notable improvements around the third month and if it's not making a big difference by the third or fourth month, that's about as good as that particular treatment will get. The problem with antibiotics is that they only really mask what's going on internally and don't tackle the root cause of the acne. For example, if your acne is hormonal, antibiotics won't really deal with that because they're not designed to.
Speaking of which, if your acne is hormonal then Dianette could be the way to go. It's not something I know a whole lot about but you should be able to find plenty of advice and information in the 'hormonal treatments' section of the message boards:
http://www.acne.org/...actone-bcp-etc/
Don't be discouraged if you're starting to break out as a result of beginning a new treatment as that's often the way it goes and could actually be taken as a positive sign because your skin's reacting and that initial purging is hopefully what will lead to it clearing up.
I also used to think that a breakout meant the product wasn't working and so I'd try something else which would then trigger an initial breakout of its own so I'd just end up going from one to the next. The key thing is time and patience because it could take perhaps a couple of months for things to start happening and for the results to really show. With that in mind, I'd suggest sticking with it because one week is no time at all for it to really get to work.
I know how discouraging it can be when things get worse like that but it will pass and things will improve. Not always easy to see the light at the end of the tunnel but you can get there and in the meantime, you can certainly say that you're taking positive steps to clear your skin. It's very much about trial and error and about finding what works best for you because each case is different. The best way to look at it is to think that for every treatment or medication you've tried that hasn't worked, it brings you a step closer to finding the thing that will work for you.