A regex might be the easiest at this point:

$results = "Home Town, Log in activity: 57 DI activity: 13 FA activity
+: 13 FAI activity: 4 Login activity: 23 Not Found activity: 4";

my @values;
$results =~ s/[^:]*: (\d+)/push @values, $1/eg;
print $_, "\n" foreach @values;
__OUTPUT__
57
13
13
4
23
4
[download]

This will push each number into the @values array.