backslashes on regular expression matches?

[strange1]

Lets say I have this string:

This Is a test - called "test"

I run 2x eregi_replace() on a string that does the following

$string = eregi_replace('([^a-zA-Z0-9. \"])','\\1\\',$string);

which adds to any special chars with a backslash at the start&end of it.

and

$string = eregi_replace('([ +])','\\1 ',$string);

which adds a backslash to the start of any backspace found.

so my result of above is:

This\ Is\ a\ test\ -[COLOR=red][/COLOR] called\ \"test\"

1) How can I get both eregi_replace()-arguments into one?
2) How can I fix the issue with the backslashes? As I would like to have a result like this:

This\ Is\ a\ test\ -\ called\ \"test\"

so there's no double \

Thanks in advance!