Improving Medicare Coverage Act This bill temporarily expands eligibility for Medicare. It also temporarily establishes a premium and cost-sharing assistance program for low-income beneficiaries. Specifically, the bill lowers the age of eligibility for Medicare from 65 to 60. The Centers for Medicare & Medicaid Services must establish procedures to provide for automatic enrollment of qualifying individuals. Enrollment must be completed within 11 months of the bill's enactment. The bill also establishes a program under Medicare to assist low-income Medicare beneficiaries with premiums, coinsurance, deductibles, and other costs. Currently, such assistance is provided through Medicare Savings Programs, which are administered by state Medicaid programs. The bill also establishes a related special enrollment period under Medicare, expands eligibility for assistance to beneficiaries with income up to 200% of the federal poverty line, and provides for joint eligibility determinations with respect to the bill's program and the low-income subsidy program under the Medicare prescription drug benefit. The bill's provisions generally take effect six months after the bill's enactment and terminate five years later.