URGENT: Need help on parsing TEXT data...

Hi,

I have a table called "Products" which contains a column called "ProductDetails" of "TEXT" datatype. What's being stored in this "ProductDetails" column is a bunch of text data such as:

"<wddxPacket version=''1.0''><header/><data><struct><var name=''PROPERTYLIST''><array length=''16''><string>PCTYPE</string><string>CONDITION</string><string>Manufacturer</string><string>CPUBrand</string><string>CPUSpeed</string><string>Memory</string><string>HardDrive</string><string>DISPLAYSCREENSIZEDIAGONAL</string><string>OPTICALCDORDVDDRIVES</string><string>OPERATINGSYSTEMWITHLICENSE</string><string>ACADAPTERCHARGER</string><string>BATTERY</string><string>DOCKINGSTATION</string><string>WIRELESSNETWORKING</string><string>SERIALNUMBERVISIBLE</string><string>SELECTOPTIONTOWIPEHARDDRIVEANDREMOVEPERSONALDATA</string></array></var><var name=''ITEM''><struct><var name=''RECEIPTKEY''><string>12341566</string></var><var name=''SERIALNUMBER''><string>34151461646</string></var><var name=''ITEMCOST''><string>0</string></var><var name=''MANUFACTURER''><string>Dell</string></var><var name=''ITEMTITLE''><string>PC NOTEBOOK</string></var>......."

I'm trying to extract (retrieve) the value inside the <string> tag which is containded inside "<var name='SERIALNUMBER'></var>" or "<var name="SERIALNUMBER"></var>", which looks like below:
<var name='SERIALNUMBER'><string>456456</string></var> OR <var name="SERIALNUMBER"><string>345657689</string></var>

Below is the query that I need help with so that I can return "456456" and "345657689" in Column1:

select Column1, Column2, Column3 from Products where (ProductDetails like '%<var name='SERIALNUMBER'>%' or ProductDetails like '%<var name="SERIALNUMBER">%)

NOTE: NOT all ProductDetails in the table have "<var name='SERIALNUMBER'>" or "<var name="SERIALNUMBER">"

This is an URGENT need, so PLEASE HELP!!!!

Many thanks in advance.