I think having money in a business acount is only if you are setting up a company ie (xxxxxx S.L.) - yes it is difficult if you dont speak Spanish and I think taking professional advice is a good idea. My Spanish partner and I used an abogado to setup our company - in other words even the Spanish use the professionals for this! Some more idea on what you need to produce:
Investor/Self-employed Visa
This visa allows you to reside in Spain as a self-employed person, or as
a worker in a company in which you have invested the required capital.
Apply to the Spanish embassy, or to your local consulate, in person, and
by previous appointment. You must submit the following documents:
? A passport valid for a minimum of six months, plus three photocopies
of the personal information and photo page
? Money order for $100 to cover processing charge
? Four recent passport-size pictures
? A certificate of good conduct issued by the police department of the
places where you?ve lived for six months or more during the past five
years, along with a translation into Spanish
? A medical certificate printed on a doctor?s letterhead, stating that
you are free from yellow fever, cholera, the plague, drug addictions,
and mental illness, and fit to undertake the proposed activity in Spain,
along with a Spanish translation
? A copy of the work authorization application (s/olicitud de permiso de
trabajo/), filed with the Ministry of Labor in Spain (this document must
be submitted at the consulate general within 30 days from the date stamped by the Ministry of Labor in Spain), along with one photocopy
? Proof of medical insurance coverage in Spain, plus two photocopies
? Original marriage certificate (if applicable), plus two photocopies
? Original birth certificates of children (if applicable), plus two
photocopies.
Processing the application will take approximately four months.
Note: Your local Spanish consulate will provide information on U.S.
citizenship and dual nationality. Since 1990, following a new
interpretation of federal laws concerning U.S. nationality, it?s
possible to become a foreign national without endangering your U.S.
citizenship. As a result, you may acquire Spanish nationality without
losing your U.S. citizenship.