Why don't you have an account here? Even if all you save is $1,000, that's better than nothing.
In theory, assuming that you have no other expenses than the £700 you listed above (ignoring the other points about clothing/transport/medical/etc), if the ECO is fine with that, then you just need to raise the shortfall each week up to the £100.95. (I doubt this will be the case, but let's just go with the happiest scenario for the moment.)
£300/mo * 12 months / 52 weeks = £69.23/week extra after rent/taxes/utilities
£100.95 - £69.23 = £31.72 needed to meet maintenance amount per week
£31.72/week * 52 weeks / 12 months = £137.45/month ($222.83 at today's exchange rates)
$222.83 * 6 months = $1,336.98
If you can save up $1,336.98, you can prove that you'll meet the £100.95/week requirement for 6 months with your husband's £1,000/mo and your savings. Please note: that still may not be enough to satisfy the ECO, especially since your budget above is very light on expenses (my normal budget has about 40 different spending categories, not just 3, for example. Even factoring out anything car/house related, I still have about 25 different things that I pay for on a regular and/or annual basis).
If I were you, I would:
1. get a job ASAP and work on saving that $1,366.
1a. If you can double that amount, great.
2. Hope that your husband gets overtime/a promotion/etc, as that will speed up the process.
3. Open a bank account in the US for you, and one in the UK for him.
4. Have your paychecks direct-deposited into your bank accounts.
5. If you can, have as many of your expenses direct-debited from your bank accounts as well, to show clear cash flow (rather than having "Cash withdrawal - $100", and submitting a receipt for a bill for $100)
Re-do your budget figures in 1, 3, and 6 months (or every month if you'd prefer). Once you hit the £100.95, keep going until you've saved up enough for the visa fee as well (hopefully this will only take another couple of weeks). At that point, if everything else looks good (no changes in lifestyle/expenses/etc), apply.
Just my $0.02.