Hello @arman960
Your Via 1525 is a Nav3 device.
To install a new map, the best tool is TTActivator, directly in the 4Gb internal memory.
Installing a bigger new map in the SD card (8Gb or 16 Gb) will first need to save the map on your laptop hard disk.
Then in addition use RLink Explorer (and some skill) to transfer the map to the SD card.
Have a search in the forum :
Tutorial