hi i need help i have a imac 10.6.8 and i cant download anything itunes later osx and my itunes isnt recognising my iphone or any one elses

This is my computer model and information and i need help, I cant download itunes update or any later edition of os x to support these downloads and itunes is not recognizing my iphone or anyone elses

Model Name: iMac

Model Identifier: iMac5,2

Processor Name: Intel Core 2 Duo

Processor Speed: 1.83 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 2 MB

Memory: 2.5 GB

Bus Speed: 667 MHz

Boot ROM Version: IM52.0090.B09

SMC Version (system): 1.6f0

Serial Number (system): W8******WH5

Hardware UUID: 00000000-0000-1000-8000-0016CB9A73D3