Endian-ness is important, but it has nothing to do with ASCII: ASCII is a display code based on 7 or 8 bit values, and Endian ness is concerned with how 8-bit values are assembled i9nto a larger number. Big Endian stores the most significant byte first in memory, Little Endian store the Least significant first.
As ASCII "2345"
Big endian 32333435 or decimal 842216501
Little Endian 35343332 or decimal 892613426
Looking at the sample data quickly, it does not look like "good" ASCII, but what it is exactly is a mystery.
You should talk to the people who created the GPS device - they should provide technical support and will know more about their product than we will. If they don't, then find another supplier and demand your money back!