upgrade php4 to php5 & mysql4 to mysql5

Hi, I need someone who is proficient with linux installation processes. I have a server that is currently configured with PHP4 and MySQL4 ( I think ). I need to upgrade to PHP5 and MySQL5 and as this is not something I have done very often, would prefer to find someone who know's exactly what they are doing. I need this to be completed by 4th of March (next 4 days). This server is currently being used for an eSupport service and I can re-direct traffic to another server whilst the upgrade is being carried out. However, the eSupport service will continue to be run from this server once the upgrade has been completed. Cheers, Gary Grant