Replacing a Selle Italia X1

On my Specialized i have a Selle Italia X1, it is showing its age now and I would like to replace it. Could anyone recommend a saddle that would have the same shape but that could be a bit more comfortable. For example the other day i did over 50 miles and the last miles it really started to hurt my butt (I realise that it may due to the fact that I just need to spend more time on the saddle). Can't really spend too much (spent a fair bit on the bike funds for the last few weeks). Thanks for any recommendation/advice.

JC