Of course you said not to spend more than five minutes on it, but I
figured I could slide by with "sleeping" on it and then doing the five
minutes of research!
My first thought is that perhaps you are short-selling your
self-assessed math skills. If you live near a major university, or
even a community college, chances are they would have some sort of
math assessment test that prospective enrollees might be allowed to
take, to get a better idea of what courses would be appropriate in
mathematics and related areas.
I did find an online, self-administered 9th grade math assessment test
that you can try:
Unfortunately "mathematics assessment" is quite the political buzzword
these days, so it was hard to find a great resource for you on this
score. But by all means double check your self-assessment.
My second thought is that a college level linear algebra course is
actually not beyond the reach of someone with the motivation and the
required high school algebra background. I've taught this course to
several groups of high school students, either in a vanilla flavor or
with an emphasis on doing some microcomputer graphics in BASIC. These
were relatively small groups, 8-15 students, and I may be biased in my
optimism, but I think they generally "get" the material as well as
college students do.
If there's a good calculus background when you take linear algebra,
you are able to get more out of the material (interesting examples,
applications, etc.), but calculus is by no means a necessary
prerequisite for linear algebra (despite the order in which these
courses will typically be taken).
As far as books, the Schaums Outline series is a possibility, though
my own experience with them is that they are too dry to hold my
interest and not quite organized or thorough enough to serve as
reference material. I'm more impressed with the "dummies" type of
books, though here the success rate is variable. I found this on
Amazon, and it seems to be well-rated:
[The Complete Idiot's Guide to Calculus]
Math skills, like many, are largely dependent on repetition for speed
and accuracy. It helps to have a work environment in which one's math
skills can find a meaningful application, even if the end results
(setting up a work schedule or tuning production output by shuffling
resources) can be kind of mundane. The drill of defining the
unknowns, down to their units of measurement and so forth, turns out
to be a real world skill of some importance, at least in my experience
in software maintenance and development.
Good luck with your quest, I know (from a bit of tutoring work as well
as teaching) that it can be tough for returning adult students to get
back into the swing of studying. It might be helpful to find a study
partner or study group to provide focus and encouragement.