Your frustration with the loss of Rosetta is understandable. Here is a recent post I assembled for a similar problem as yours:
Unfortunately you got caught up in the minor miracle of Rosetta. Originally licensed by Apple when it migrated from the PowerPC CPU platform that it had used from the mid-1990's until the Intel CPU platform in 2006, Rosetta allowed Mac users to continue to use their library of PPC software transparently in emulation.
However, Apple's license to continue to use this technology expired with new releases of OS X commencing with Lion (and now Mountain Lion). While educational efforts have been made over the last 6 years, the fact is that Rosetta was SO successful that many users were caught unaware UNTIL they upgraded to Lion or Mountain Lion.
Workarounds:
1. If your Mac will support it, restore OS X Snow Leopard;
2. If your Mac will support it, partition your hard drive or add an external hard drive and install Snow Leopard into it and use the "dual-boot" method to choose between your PowerPC software or Lion/Mt. Lion;
3. Upgrade your software to Intel compatible versions if they are available, or find alternative software that will open your data files, modify them and save them;
4. Install Snow Leopard Server (with Rosetta) into Parallels or VMWare Fusion. Apple is now selling Snow Leopard Server for only $19.99 + sales tax & shipping; call 1.800.MYAPPLE (1.800.692.7753). This solution will give you concurrent use of your PowerPC applications and access to Lion or Mt. Lion.
As it may be possible you are not in the USA, I am getting reports that Snow Leopard Server is not available for sale directly from the Apple Store outside the USA. I do not know about the UK.
So then you would either need an intermediary to purchase Snow Leopard Server for you in the USA and ship it to you, or, another suggestion is:
The installation of Snow Leopard (client) into Parallels.
Snow Leopard client installation instructions still available here:
http://forums.macrumors.com/showthread.php?t=1365439
[click on image to enlarge]
NOTE: Computer games with complex, 3D or fast motion graphics make not work well or at all in virtualization