Sears no longer makes the replacement filter for the 113.177135 two gallon vacuum cleaner. The original part number of the filter was 9-16949 or 16949.
Luckily there is an aftermarket replacement filter that fits almost perfectly. The filter is the Vacmaster VRC5. Although it says it is made for 5 to 16 gallon shop vacs, it fit well on my Sears 113.177135 two gallon Clean Carry vacuum. I bought a three pack of the cloth filters on eBay for about $12.00. The dimensions of the VRC5 filters are 10 inches wide at the bottom with the filter flattened out, and about 9.5 inches long. It has a sewn-in elastic collar at the top that holds the filter in place on the cage inside the vacuum.
The dimensions of the cylindrical plastic cage inside the vacuum are 5.5 inches in diameter by about 5 inches long. Although the Vacmaster VRC5 filter is longer than five inches, it is tapered, so it fits almost perfectly.
I had a hard time finding information on replacement filters on the web, so I hope this information is useful for you.