You don't need Win32::API nor compiler, to access those values. It can all be done using Win32 that comes with AS Perl's.

Given a dll that contains this exported integer (compiled as test.dll):

__declspec(dllexport) int testint = 12345;
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That might be accessed from a C program so:

#include <windows.h>
#include <stdio.h>

int main( int argc, char **argv ) {
    HMODULE hm = (HMODULE)LoadLibrary( "test.dll" );
    int *ptestint = (int *)GetProcAddress( hm, "testint" );

    printf( "Addr: %x Value: %d\n", ptestint, *ptestint );
    return 1;
}
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It can be accessed from (AS) perl as follows:

#! perl -slw
use strict;
use Win32;

my $dll = Win32::LoadLibrary(
    'test'
) or die $^E;

my $proc = Win32::GetProcAddress(
    $dll, 'testint'
) or die $^E;

print unpack 'V', unpack 'P4', pack 'L!', $proc;
__END__
C:\test>\perl32\bin\perl.exe 773754.pl
12345
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The complicated bit is the last line:

1. pack 'L!', $proc converts the UV returned by GetProcAddress() back into a binary value;
2. unpack 'P4', ... fetches 4-bytes (the exported integer) from that address;
3. unpack 'V', ... converts those 4-bytes into a perl scalar;

Assuming that your running on a platform where int and long and synonymous, that should work for all three values. Otherwise you'll need to adjust the 'V' for the last one.