If you have liquid assets, you could transfer them to US citizen petitioner to hold in a US bank account, and then provide a copy of that bank account statement showing the balance amount to use as an asset.
NOTE: assets are only valued at 1/3 income, that is if income falls below the line by 1000, then 3000 in assets are needed to make up the difference.
Useful info from London Embassy:
QUOTE
Applicants Own Funds
An applicant who expects to be able to meet the public charge provisions of the law through personal financial resources may submit to the consular officer evidence of funds or income from one or more of the following sources:
- bank statement showing present balance of applicant's account, date account was opened, the number and amount of deposits and withdrawals during the past 12 months, and the average balance during the year. If there have been recent unusually large deposits, an explanation thereof should be given;
- proof of ownership of property or real estate, in the form of a title deed or the equivalent and a letter from a lawyer, or real estate agent showing its present valuation (any mortgages or loans against the property must be stated);
- letter or letters verifying ownership of stocks and bonds, with present market value or expected earnings indicated;
- statement from insurance company showing policies held and present case surrender value;
- proof of income from business investments or other sources.
If the financial resources are derived from a source outside the United States, a statement as to how the funds or income are to be transferred to the U.S. must be provided.