English student wants PHd in Finance

I don't mean to discourage you, but you will not have a chance at a finance or an economics PhD as your profile currently stands. Both are highly quantitative subjects which at a minimum require sufficient knowledge of undergraduate economics, mathematics and statistics. Your GMAT score is an important element (although bear in mind that you will need a GRE score for an Econs PhD) of the application process, but it will not be enough to make up for the absence of those courses. You may wish to consider the possibility of a business PhD with a more qualitative/behavioural inclination assuming your undergraduate studies in literature included a significant sociology or psychology component.

If you are set on pursuing a PhD in economics or finance, you will need a Master's. Even for a qualitative subject, even if not essential, I would recommend an academically oriented Master's as well to showcase your academic potential given that your undergraduate studies have apparently not shown you in the best light.

Getting into a Master's program (for econs/finance) will be difficult as well but not impossible. One possible route, if you're willing to study overseas, would be University College London's Graduate Diploma in Statistics (though they favour applicants with some mathematical background), progressing to a Master's the following year. Bear in mind that this program is highly competitive.

Another option would be to undertake either the graduate diploma in Economics or Mathematics through the University of London's External System. I know 'distance learning' is thought to be a bit of a dirty word but you can be assured that (in the UK and most of the Commonwealth at least) the University enjoys a good reputation, though obviously not as strong as physically studying at one of its constituent colleges but enough to know that the qualification is worth something. At any rate, should you wish to pursue that path you should treat the diploma as a stepping stone to a Master's.

Again, I do not wish to discourage you. As things stand, you need to know that there is virtually no chance of you entering a PhD program of any worth in your chosen field/s. However, if you're certain that a PhD in finance or economics is for you, all building a competitive application requires is a bit more time, effort and money.

Good luck.