Convert string to decimal

[Chris Murphy]

I have a problem. I need to convert a portion of a string to a decimal. The string looks as follows:

'£10.50/month. 100 minutes. 500 texts. 24 months.'

I want to break out the 10.50 section and store it in a variable using php so i can allow customers to filter the results from my table by this value.

I am using mySql (phpmyadmin).

I cannot ammend the structure of the table because its provided by a third party.

How can i achieve this???

Hope I have given enough information, if not please ask.