I wouldn't feel right giving you advice about how to improve your Latin solo at this point, since I would not have tried my own advice. While most of the memorizing of forms is done when you finish the textbook, there is still much to learn from reading and study (my reading ability increased dramatically just by reading the first two books of the Aeneid). It is very hard to focus yourself on topics weak or foreign for you while outside the confines of a textbook if you do not have an instructor, so I recommend that you try to find a Latin class if that is possible. There are advanced textbooks around, mostly prose compositions, and that may bring your Latin to a higher level, but will not do much to help you read better. Do not restrict yourself to Wheelock's recommended reading; I hate to say it, but the book trains you to read the Loci in the back, not the wide array of classical literature. They hold your hand for longer than most books, but they still inevitably leave the final step to you in a rather haphazard way.
Also, you do not have to read authors like Cicero right away; don't even read all those passages in the back if you don't want to. Start with some easy Catullus, Phaedrus, Vulgate (what is that doing there?!) etc.; then move up to Horace, Pliny, Martial, Caesar etc.; then Cicero, Vergil, Tacitus, etc. Remember that you are not just learning Latin, you are learning to read the greatest and most complex authors of Latin. It takes a while to adjust to a a sophisticated style in your own language, it takes even longer to do so in your second language. Also, if it hasn't hit you yet, it's time to stop translating and start reading it in Latin (hopefully this process was started in advance).
flebile nescio quid queritur lyra, flebile lingua murmurat exanimis, respondent flebile ripae