you can download this new wallet and run it, after sync you will have you coin.
IMPORTANT : DON'T DELETE the folder where is the wallet.dat (app data/roaming/mintcoin).
For more security you start your old wallet (1.2) and make a backup of it. Then download and open zip files with 1.3. start it and sync. Shouldn't be problems, but backup is strongly reccomended.
Or you can add this node list to your config, sync and then save the backup.
addnode=113.135.133.39
addnode=115.28.140.128
addnode=62.233.34.246
addnode=162.243.35.172
addnode=88.164.227.110
addnode=176.14.145.130
addnode=125.39.130.15
addnode=123.53.221.104
addnode=198.144.159.39
addnode=184.75.214.42
addnode=113.69.22.36
addnode=86.26.190.235
addnode=153.19.215.115
addnode=115.28.134.205
addnode=223.152.73.253
addnode=122.178.204.154
addnode=115.28.162.160
addnode=81.108.157.78
addnode=180.112.221.68
addnode=120.144.87.195
addnode=31.53.158.152
addnode=50.102.222.206
addnode=60.182.177.105
addnode=217.118.83.145
addnode=119.119.151.106
addnode=218.77.97.176
addnode=182.112.134.112
addnode=106.68.126.251
addnode=195.38.122.80
addnode=162.243.4.85
addnode=62.221.120.216
addnode=49.66.59.73
addnode=124.168.123.204
addnode=223.198.48.85
addnode=162.223.48.19
addnode=212.247.109.253
addnode=188.162.40.67
addnode=24.49.13.97
addnode=203.208.83.100
addnode=91.2.7.117
addnode=80.123.21.76
addnode=14.148.0.173
addnode=64.58.130.180
addnode=89.168.237.30
addnode=122.224.95.209