You should have quoted me, I would have replied earlier
I actually understand how you feel about going to University. I was denied the chance to go to University in 2012 when I was 18 and it made me very sad. I am 20 now and if all goes well this year I should be starting a Mathematics degree at a reputable University in 2015.
I am completely self-taught for Mathematics so I have no references to vouch for my ability, thus I am going to find a private tutor, demonstrate my ability and ask for a reference. Of course I will go for further lessons with them as I am also doing Additional Further Mathematics as well as STEP 2 and 3.
Wow, that is cheap! It is pretty close by car too :| I will ask if the hold the STEP exams and if so I will do my exams with them, thank you!
Since you say most of what you have learned is based on the Further Maths syllabus then you'll blaze through A-Level Maths, giving you plenty of time for Economics and Further Maths.
Lastly, here is how I self-study:
Mathematics
I watch tutorials from ExamSolutions, Khan Academy, M4ths.com and then complete exercises from the EdExcel books as well as MyMaths from time to time. I shall be signing up to LiveMaths as they have content the websites I mentioned do not have.
Economics
I actually have a
thread for AS Economics if you'd like to take a look. I am not too sure about what A2 will be like so I cannot comment on how long it will take to learn.
To conclude this post I think you should apply for entry in 2015. You should be able to if you have good predicted grades from your tutors as well as a great personal statement. I wish you the best of luck