I don't know about repairing the OEM remote or transferring its programming.  However, Denon IR signals are well known, and this site has two CCF files for the AVC-A1SR.  It uses the standard Denon codes, so most universals will control volume/mute.

The easiest universal would be any Harmony remote.  The cheapest approach would be a Comcast DVR remote, and new ones are typically available on eBay for $6 shipped.  Or you could get a RCA RCRP05B, or Atlas cable remotes.

For these, use setup code 31360 (Comcast) or Audio 1360.  Some functions will work out of the box, and for the rest use the following 5 digit EFCs.  Assign these to buttons (except device buttons) of your choice.  Most people use the number buttons for inputs.  Use these 994 command instructions.

vol up 01973
vol down 01909
up arrow 34047
tape2/mon 02033
stereo 33923
right arrow 01921
power_on 01981
power_off 01917
power 01977
mute 01845
left arrow 33988
input mode 33879
home THX Cinema 34027
ext. in 33943
enter 01853
down arrow 33823
direct 33859
analog 01793
Zone Toggle 01920
VDP 01897
VCR-3 01993
VCR-2 01865
VCR-1 01929
V.AUX 01801
Tuner 01945
TV/DBS 01961
T.Tone 01901
System Setup 33855
Surround Parameter 33983
Surround Back 33979
Speaker 01933
SAT 01833
Pure Surround 01900
PHONO 02041
On Screen 01985
MD/Tape 01905
Dolby / DTS Surround 01821
Dimmer 33985
DVD 02045
DSP simulation 01885
Channel Select 33999
CH Level Up 33847
CH Level Down 33975
CD 01817
5CH/7CH stereo 33839