How to edit a store locator

[koala91]

I started a new job recently and I got told to edit the store locator in our webpage. Noone knows how to do it here and I am new at managing webs using CMS Made Simple and I don't know exactly how to do it.

I found an excel listing all the stores, but I can't find any extension or anything that can help me, only this codification:

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{literal}

<![if !IE 8]>
<__script__ language="javascript">
function GEOprocess(position) {

GEOajax("geo.php?accuracy=" + position.coords.accuracy + "&latlng=" + position.coords.latitude + "," + position.coords.longitude +"&altitude="+position.coords.altitude+"&altitude_accuracy="+position.coords.altitudeAccuracy+"&heading="+position.coords.heading+"&speed="+position.coords.speed+"");
document.getElementById("buscar").value = 'Localizando tu posicion';
}

function GEOdeclined(error) {
document.getElementById("buscar").value = 'Donde: ej. (Balmes, 3 Barcelona)';
}

if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(GEOprocess, GEOdeclined);
}else{
alert("Tu navegador no permite la geolocalización");
}

if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}else if(window.ActiveXObject){
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}

function GEOajax(url) {
xmlHttp.open("GET", url, true);
xmlHttp.onreadystatechange = updatePage;
xmlHttp.send(null);

}

function updatePage() {
if (xmlHttp.readyState == 4) {
var response = xmlHttp.responseText;
document.getElementById("buscar").value = '' + response;
}
}

</__script>
<![endif]>
{/literal}
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I would be so grateful if anyone could help me since I am terribly lost.

Thank you so much in advance!