The overclock for those is the BSEL tape mod from 266 to 333 fsb on the E7500 2 core CPU. This gets about 3.67Ghz
This was used on the Q6600 to 3GHz back in the day, but the Q9650 runs about 10% better so isn't used for that any more.
https://a4.pbase.com/o6/45/326445/1/92337793.tD8VEvab.Tape_1333.jpg
You might get lucky with an E7600 but usually there isn't enough CPU Volatge for the 3.83GHz overclock.
If you have the Mini Tower case the Zotac GTX1050 Mini drops right in. It's just about the only GPU that fits.
You could use the Zotac GTX1050TI Mini 4GB also. But the 8GB DDR2 system will choke occasionally on a few benchmarks.
A D9729 cooler, or T9303 will easily cool that setup. Get whichever one matches the holes in you...