Ok to answer at the first questions i have a 550W PSU that i installed together with a gtx660 3 years ago. Sadly last week the 660 died ;no idea why, since the fans are moving but the motherboard doesnt recognize it anymore and had to switch back to the "integrated" 620. Since the i started to look for a good alternative for about 100-130 Euros and came across the 1050 but im not sure if the old motherboard can run it. Btw here are some other specs from Speccy:
Motherboard
Manufacturer ASUSTeK COMPUTER INC.
Model CM6340 (LGA1155)
Version Rev X.0x
Chipset Vendor Intel
Chipset Model Ivy Bridge
Chipset Revision 09
Southbridge Vendor Intel
Southbridge Model P75/B75
Southbridge Revision 04
System Temperature 34 °C
BIOS
Brand American Megatrends Inc.
Version 0604
Date 11/07/2013
CPU
Intel Core i5 3470
Cores 4
Threads 4
Name Intel Core i5 3470
Code Name Ivy Bridge
Package Socket 1155 LGA
Technology 22nm
Specification Intel Core i5-3470 CPU @ 3.20GHz
Family 6
Extended Family 6
Model A
Extended Model 3A
Stepping 9
Revision N0
Instructions MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, Intel 64, NX, VMX, AES, AVX
Virtualization Supported, Disabled
Hyperthreading Not supported
Fan Speed 1042 RPM
Bus Speed 100.0 MHz
Stock Core Speed 3200 MHz
Stock Bus Speed 100 MHz
RAM
Memory slots
Total memory slots 4
Used memory slots 2
Free memory slots 2
Memory
Type DDR3
Size 8192 MBytes
Channels # Dual
DRAM Frequency 799.9 MHz
If you have some other options for a new GPU i will gladly take any info from more experienced people.
As i said i have a budget of 100-130 Euros and i mainly use pc for gaming.
Im used to play games like Dark Souls 3 or GTA 5 on medium-high settings with 1900x1600 resolution (monitor limit)